Enjoy fast, free delivery, exclusive deals, and award-winning movies & TV shows with Prime
Try Prime and start saving today with fast, free delivery

Get Fast, Free Shipping with Amazon Prime FREE Returns

FREE delivery Friday, May 16 to Nashville 37217 on orders shipped by Amazon over $35

Or Prime members get FREE delivery Wednesday, May 14.

In Stock

$$26.99 () Includes selected options. Includes initial monthly payment and selected options. Details

Enhancements you chose aren't available for this seller. Details

${cardName} not available for the seller you chose

${cardName} unavailable for quantities greater than ${maxQuantity}.

Ships from

Amazon

Sold by

CHINCHY Karseell

Returns

30-day refund/replacement

Payment

Secure transaction

Add a gift receipt for easy returns

FREE delivery Friday, May 16 to Nashville 37217 on orders shipped by Amazon over $35

Or Prime members get FREE delivery Wednesday, May 14.

In Stock

Deliver every:

$$26.99 () Includes selected options. Includes initial monthly payment and selected options. Details

Enhancements you chose aren't available for this seller. Details

${cardName} not available for the seller you chose

${cardName} unavailable for quantities greater than ${maxQuantity}.

Auto-deliveries sold by CHINCHY Karseell and Fulfilled by Amazon

9 VIDEOS

Karseell Collagen Hair Treatment 16.9 OzCHINCHY Karseell

Image Unavailable

Image not available for
Color:

To view this video download Flash Player

Karseell Collagen Hair Treatment 16.9 Oz 500ml Deep Repairs Conditioner Argan Oil Keratin Hair Treatment for Dry Damaged Curly Bleached & All Hair Types

Visit the Karseell Store

835 ratings

| Search this page

Amazon's Choice

$26.99 $1.60 per fluid ounce

Get Fast, Free Shipping with Amazon Prime

FREE Returns

Get Fast, Free Shipping with Amazon Prime

FREE Returns

Brief content visible, double tap to read full content.

Full content visible, double tap to read brief content.

Size: 16.9 Fl Oz (Pack of 1)

{"desktop_buybox_group_1":[{"displayPrice":"$26.99","priceAmount":26.99,"currencySymbol":"$","integerValue":"26","decimalSeparator":".","fractionalValue":"99","symbolPosition":"left","hasSpace":false,"showFractionalPartIfEmpty":true,"offerListingId":"OQNokoOq80BfoNg41GkAWI1ZrYd2sfAi5YgoFjgOWG3Wc%2BbCSTdBoJMOh6Y%2FOSDdTfgPmy6Y1HOD4DHw5zl%2Bsa2raw2AaPkCnPea5MjDjYvvJDs012LzT%2Bcxb0rIFH7ivJ2veb5w1LcWA0eOaBjMBvEE8lwGvw%2FuGgru83Kfw9bnNfSsm9iMtB2vRcAdAqrg","locale":"en-US","buyingOptionType":"NEW","aapiBuyingOptionIndex":0}, {"displayPrice":"$25.64","priceAmount":25.64,"currencySymbol":"$","integerValue":"25","decimalSeparator":".","fractionalValue":"64","symbolPosition":"left","hasSpace":false,"showFractionalPartIfEmpty":true,"offerListingId":null,"locale":"en-US","buyingOptionType":"SNS","aapiBuyingOptionIndex":1}]}

Purchase options and add-ons

Brand	Karseell
Item Form	Cream
Hair Type	Dry and Damaged Hair
Product Benefits	Nourishing, Hydrating, Moisturizing
Age Range (Description)	Adult

About this item

✔ MOISTURIZE AND NOURISH | Argan oil is rich in vitamin E. It can repair the split ends of the hair, moisten the hair and bring a shiny luster. It's a great natural ingredient for dry and damaged hair moisturizing hair and protecting against UV damage.
✔ PACKAGING DESIGN | Karseell collagen hair treatment, with a unique design of the bag, to prevent contact with light, air and moisture. At the same time, it can save space, freely use and fold.
✔ HIGH QUALITY INGREDIENTS | Made of high quality ingredients from herbs selected from all over the world. Natural material heals your hair with Karseell packet hair mask.
✔ PROFESSIONAL USE RANGE | This collagen hair mask suitable for family use, travel, hairdressing salon and advanced care. Karseell is committed to making professional hair products.
✔ QUALITY ASSURANCE | Karseell hair care strives to provide customers with the ultimate service experience. If there is any problem with the collagen hair treatment, no reason to REFUND or RETURN.

› See more product details

Report an issue with this product or seller

Similar item to consider

Amazon Basics Moisture Rich Conditioner, 28 Fluid Ounce

28 Ounce (Pack of 1)

(3154)

$11.05 ($0.39/ounce)

New to Amazon!

Makeup that lives up to the hype | Explore now

This item: Karseell Collagen Hair Treatment 16.9 Oz 500ml Deep Repairs Conditioner Argan Oil Keratin Hair Treatment for Dry Damaged Curly Bleached & All Hair Types

$26.99 ($1.60/fluid ounce)

Get it as soon as Friday, May 16

In Stock

Sold by CHINCHY Karseell and ships from Amazon Fulfillment.

Karseell Moroccan Argan Oil for Hair Healing Cold Pressed Weightless Argan Oil Hair Serum for Dry Damaged Hair 50ml

$16.99 ($10.05/fluid ounce)

Get it as soon as Friday, May 16

In Stock

Sold by CHINCHY Karseell and ships from Amazon Fulfillment.

Karseell Argan Oil Shampoo Extract Moisturizing Deep Repair Smooth Shampoo for Dry and Damaged Hair 16.9Oz 500ml

$19.19 ($1.14/fluid ounce)

Get it as soon as Monday, May 19

In Stock

Sold by CHINCHY Karseell and ships from Amazon Fulfillment.

Total price: $00

To see our price, add these items to your cart.

Try again!

Details

Added to Cart

Choose items to buy together.

Karseell Hair Treatment Conditioner, 16.9 Fl Oz (500ml) - Deep Repairing with Argan Oil & Keratin for Dry, Damaged, Curly, Bleached Hair

Amazon's Choice

1 offer from $1499
Karseell Repair Conditioning Argan Oil Collagen Hair Mask Essence for Dry Damaged Hair All Hair Types 200ml 6.78 fl.oz

1 offer from $1599
LA'DOR Hydro LPP Keratin Hair Treatment - Anti Frizz Conditioner Mask for Dry, Damaged, Color Treated, Gray Hair - Hydrolyzed Collagen (3. 16.9 Fl Oz)

1 offer from $2199
GK HAIR Global Keratin Deep Conditioner Masque (33.8 Fl Oz/1000ml) Intense Hydrating Repair Treatment Mask for Dry Damaged Color Treated Frizzy Hair Restoration Formula with JOJOBA Seed Oils

3 offers from $9799
LA'DOR Hydro LPP Keratin Hair Treatment - Anti Frizz Conditioner Mask for Dry, Damaged, Color Treated, Gray Hair - Hydrolyzed Collagen (2. 5.07 Fl Oz)

1 offer from $1699
1 sustainability feature
Sustainability features
This product has sustainability features recognized by trusted certifications.
Packaging efficiency
Reduced air and/or water in the product or packaging for more efficient transportation.
As certified by
Compact by Design (Amazon-developed Certification)
Compact by Design (Amazon-developed Certification)
Compact by Design identifies products that, while they may not always look very different, have a more efficient design. By reducing water and/or air in the product or packaging, these become more efficient to ship. At scale, these small differences in product size and weight lead to significant carbon emission reductions.
Discover more products with sustainability features.Learn more
COSMOO Hair Mask for Damaged Hair-Collagen Coating Hair Protein Treatment 155ml/5.46 fl oz, Deep Conditioning Hair Mask for Dry Damaged Hair, Fortifies, and Helps Prevent Split Ends and Hair Breakage

1 offer from $949

From the brand

About us

We were founded in 2005 and specialize in hair care. Karseell is the perfect choice to give you the hair you’ve always wanted.

Our products are made with all natural and organic ingredients that nourish and restore your hair’s natural beauty. Karseell is all about making you look and feel your best, so that you can shine like the star you are.

Start your journey to beautiful hair with Karseell today!
Karseell Hair Treatment
Karseell Hair Mask
Collagen Hair Treatment
Hair Conditioner
Karseell Shampoo

Product Description

	Karseell Collagen Hair Treatment	Karseell Collagen Hair Mask	Karseell Hair care essential oil

Customer Reviews	835	19,380	3,130
Price	$26.99	$24.98	$16.99
Main Benefits	Intense Deep Hydration, Soft Silky Hair, Frizz Control, Split Ends Repair, Hair Strengthening and Shiny Locks.	Frizz Control and Silky Soft Hair, Extra Shine and Natural Gloss Effect, Strengthens and Protects Hair Against Heat, Split Ends Repair.	It can nourish and repair fragile and damaged hair, giving your skin and nails a fresh and beautiful glow.
Hair Rehabilitation	Dry, Damaged, Colored, Bleached, Permed, After Straightening, After Keratin Treatment	Dry, Damaged, Colored, Bleached, Permed, After Straightening, After Keratin Treatment	Dry, Damaged, Colored, Bleached, Permed, After Straightening, After Keratin Treatment
Sulfate Free	✓	✓	✓
Paraben Free	✓	✓	✓
Cruelty Free	✓	✓	✓
Hair Rehabilitation	✓	✓	✓

Product details

Product Dimensions ‏ : ‎ 11.02 x 7.48 x 2.36 inches; 1.1 Pounds
Item model number ‏ : ‎ Collagen Hair Mask Treatment
UPC ‏ : ‎ 050132158674
Manufacturer ‏ : ‎ Karseell
ASIN ‏ : ‎ B08LBFT4SR
Country of Origin ‏ : ‎ China

Best Sellers Rank: #38,727 in Beauty & Personal Care (See Top 100 in Beauty & Personal Care)
- #246 in Hair Treatment Masks

Customer Reviews:
835 ratings

Compare with similar items

	This Item Karseell Collagen Hair Treatment 16.9 Oz 500ml Deep Repairs Conditioner Argan Oil Keratin Hair Treatment for Dry Damaged Curly Bleached & All Hair Types	Recommendations Karseell Hair Treatment Conditioner, 16.9 Fl Oz (500ml) - Deep Repairing with Argan Oil & Keratin for Dry, Damaged, Curly, Bleached Hair	Karseell BNC Collagen Hair Treatment Deep Repair Conditioning Argan Oil Collagen Hair Mask Essence for Dry Damaged Hair All Hair Types 18.6 oz 550ml	Karseell 3.38floz 100ml Collagen Hair Treatment Deep Repair Conditioning Argan Oil Collagen Hair Mask Essence for Dry Damaged Hair All Hair Types	Karseell Conditioner Deep Restores Argan Oil Hair Treatment Smooth Glossy for Dry and Damaged Hair 500ml 16.9 Oz	Karseell Repair Conditioning Argan Oil Collagen Hair Mask Essence for Dry Damaged Hair All Hair Types 200ml 6.78 fl.oz
	Try again! Details Added to Cart spCSRF_Treatment	Try again! Details Added to Cart spCSRF_Treatment	Try again! Details Added to Cart spCSRF_Treatment	Try again! Details Added to Cart spCSRF_Treatment	Try again! Details Added to Cart spCSRF_Treatment	Try again! Details Added to Cart spCSRF_Treatment
Price	$26.99	$14.99	$14.99	-36% $12.79 List: $19.99	$23.99	$15.99
Price Per Unit	$1.60 / fluid ounce	$0.89 / fluid ounce	$0.81 / fluid ounce	$3.78 / fluid ounce	$1.42 / fluid ounce	$2.37 / fluid ounce
Delivery	Get it as soon as Friday, May 16	Get it as soon as Friday, May 16	Get it as soon as Friday, May 16	Get it as soon as Friday, May 16	Get it as soon as Friday, May 16	Get it as soon as Friday, May 16
Customer Ratings	4.6835	4.470	4.4166	4.41,921	4.6297	4.372
Sold By	CHINCHY Karseell	CHINCHY Karseell	CHINCHY Karseell	CHINCHY Karseell	CHINCHY Karseell	CHINCHY Karseell
hair type	Dry and Damaged Hair	Dry	Dry	All	Damaged	All
scent	Coconut	—	—	✗	Fresh	✗
form	Cream	Cream	Cream	Mask	Liquid	Liquid
liquid volume	16.9 fluid ounces	16.9 fluid ounces	18.6 fluid ounces	3.38 fluid ounces	16.9 fluid ounces	200 milliliters
product benefit	Nourishing, Hydrating, Moisturizing	Frizz Control	Frizz Control	Smoothening	Moisturizing, Nourishing	Conditioning
specialty	Sulfate Free, Paraben Free	—	Natural	Natural	Natural	Natural
recommended uses	All,Color,Conditioner,Culr Enhancer,Hair Types,Moisturizing	Sulfate Free, Paraben Free	Sulfate Free, Paraben Free	Deep conditioning and repairing dry or damaged hair, suitable for all hair types including color-treated chemically-treated to be applied 1-2 times a week nourishment reduced frizz.	Conditioner,Moisturizing	Wash your hair with shampoo (do not use conditioner). Dry with a towel without dripping water, apply an appropriate amount of conditioner to the hair, keep it absorbed for 10-15 minutes, and then rinse with clean water.
weight	500 grams	16.9 ounces	18.6 ounces	5.64 ounces	500 grams	—

Important information

Safety Information

Please do not touch your eyes and do not place in areas where children come into contact

Ingredients

Collagen, argan oil ,and herbals extracts,which help nourish,hydrate,and repair dry ,damaged hair

Directions

After shampooing (no more conditioner). Dry with a towel to no dripping state, apply proper volume of collagen on hair (Keep away from scalp), stay 10-20 min for hair to absorb, then rinse out with clean water.

Customer reviews

835 global ratings

How customer reviews and ratings work

Review this product

Write a customer review

Customers say

Customers find the hair treatment effective, with one mentioning it works particularly well on extensions. The product leaves hair soft, shiny, and manageable, with one customer noting it strengthens hair on first use. They appreciate its pleasant scent and consider it well worth the price. The moisture level receives mixed feedback - while some customers find it moisturizing, others report their hair drying out.

AI-generated from the text of customer reviews

Select to learn more

Effectiveness Hair softness Shine Scent Hair health Value for money Ease of use Moisture level

30 customers mention "Effectiveness"27 positive3 negative

Customers find that the conditioner works well, with one customer specifically noting its effectiveness on hair extensions.

"Love this hair mask! Works amazing on my hair extensions." Read more

"This is a great hair mask not too heavy great scent left hair feeling moisturized used it on many different people" Read more

"Is a nice product i give you 5 stars" Read more

"...TWO MINUTES!!!!! NO PRODUCT & NOT SECTIONED IN FOUR PARTS. I AM A BELIEVER!!!!! *..." Read more

24 customers mention "Hair softness"24 positive0 negative

Customers find that the conditioner makes their hair soft and silky, with one customer noting it leaves it feeling moisturized.

"...use it on my daughter's hair, it is well worth the price, it leaves your hair so soft, the scent is wonderful. Please give this product a try." Read more

"...This product is undoubtedly the best. My hair is incredibly soft, shiny, moisturizing, and very fragrant. I would definitely buy it again." Read more

"What I like about this product? It made my hair, very soft and silky." Read more

"...the mask thinking all the effects would go away, but my hair is still soft and not frizzy. Will be using this weekly from now on!" Read more

18 customers mention "Shine"18 positive0 negative

Customers love the shine of the conditioner and say it makes their hair look wonderful.

"Love this hair mask! Works amazing on my hair extensions." Read more

"...This product is undoubtedly the best. My hair is incredibly soft, shiny, moisturizing, and very fragrant. I would definitely buy it again." Read more

"It leaves my hair shiny and makes styling easier." Read more

"...no expectations of this product but to my surprise I have a beautiful curl pattern again...." Read more

17 customers mention "Scent"13 positive4 negative

Customers like the conditioner's scent.

"This is a great hair mask not too heavy great scent left hair feeling moisturized used it on many different people" Read more

"...it is well worth the price, it leaves your hair so soft, the scent is wonderful. Please give this product a try." Read more

"...My hair is incredibly soft, shiny, moisturizing, and very fragrant. I would definitely buy it again." Read more

"...Last long 2. Worth the money 3. Not too heavy 4. Smells great" Read more

15 customers mention "Hair health"12 positive3 negative

Customers report that the conditioner helps their hair, with one customer noting it completely transformed their hair, while another mentions it takes frizz out and keeps it smooth.

"Every one should have it, repair hair, value for money, leaves the hair super shiny" Read more

"What I like about this product? It made my hair, very soft and silky." Read more

"...I’ve been using this product for 6 months now and the frizz is gone. The first picture was taken Dec 2023 before I started using this product ...." Read more

"Doesn’t work. I’m not sure of the trick. Didn’t work for my aging hair. Has alcohol as an ingredient. Tired several times using different methods...." Read more

8 customers mention "Value for money"8 positive0 negative

Customers find the conditioner to be worth the price.

"...I also use it on my daughter's hair, it is well worth the price, it leaves your hair so soft, the scent is wonderful. Please give this product a try." Read more

"Every one should have it, repair hair, value for money, leaves the hair super shiny" Read more

"...The second picture is me now 1. Last long 2. Worth the money 3. Not too heavy 4. Smells great" Read more

"...I would definitely buy again. This one was worth the buy." Read more

6 customers mention "Ease of use"6 positive0 negative

Customers find the conditioner easy to use, describing it as very manageable, with one customer noting that only a small amount is needed.

"...curl /wavy pattern and after use; my hair felt really soft and very manageable...." Read more

"This product was easy to use and detangled any hair knots. My hair was silky. I would recommend this product. It smelled great." Read more

"...repair and hydration, leaving my hair feeling incredibly soft and manageable...." Read more

"...This solves the problem and also extended time between washes. Need very little and my hair are super long" Read more

7 customers mention "Moisture level"4 positive3 negative

Customers have mixed experiences with the conditioner's moisture level, with some finding it moisturizing while others report their hair drying out.

"This is a great hair mask not too heavy great scent left hair feeling moisturized used it on many different people" Read more

"...By the 5th use I noticed my hair drying out. It turned super dry and brittle. I through the rest out. No collagen is in this product as advertised...." Read more

"...My hair is incredibly soft, shiny, moisturizing, and very fragrant. I would definitely buy it again." Read more

"...the way my hair looked after using this per the package instructions - dry, frizzy, and now has split ends...." Read more

Reviews with images

See all photos

Top reviews from the United States

Translate all reviews to English

There was a problem filtering reviews. Please reload the page.

RockyDog
Awesome
Reviewed in the United States on March 24, 2025
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase

Love this hair mask! Works amazing on my hair extensions.

Read more

One person found this helpful

Helpful

Report
lisa j
You get all the product out of the packaging and you will use it all!
Reviewed in the United States on February 8, 2025
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
This is a great hair mask not too heavy great scent left hair feeling moisturized used it on many different people

Read more

3 people found this helpful

Helpful

Report
I’m my own chiropractor
OMG, thank God for this product!
Reviewed in the United States on October 13, 2024
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
As a child Finesse was the only product that would detangle my hair and smelled good. After seeing the ad for Karseell Collagen Hair Treatment 16.9 Oz 500ml Deep Repairs Conditioner Argan Oil Keratin, I had to try it and it did not disappoint. I also use it on my daughter's hair, it is well worth the price, it leaves your hair so soft, the scent is wonderful. Please give this product a try.

Read more

One person found this helpful

Helpful

Report
Rayza toledo
Incredible
Reviewed in the United States on May 7, 2025
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
After seeing a friend using the Karseell Collagen Hair Treatment 500ml Deep Repair Conditioner with Argan Oil tube, I decided to try it. This product is undoubtedly the best. My hair is incredibly soft, shiny, moisturizing, and very fragrant. I would definitely buy it again.

Read more

Helpful

Report
linda
Hidrata el Cabello.
Reviewed in the United States on October 31, 2024
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
Tengo más de un mes usándolo una vez a la semana y mi cabello se siente más fuerte. Sanó e hidratado… le da brillo cada vez más se usa más brillo y suavidad. Lo recomiendo.

Read more

3 people found this helpful

Helpful

Report
Translate review to English
Estevez
Karseell
Reviewed in the United States on April 21, 2025
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
Este producto es el mejor, ya lo he comprado dos veces, me encanta porque me deja el cabello suave y con mucho brillo. Sin duda alguna es un buen producto y huele riquísimo. 😍😍

Read more

Estevez

Karseell

Reviewed in the United States on April 21, 2025
Este producto es el mejor, ya lo he comprado dos veces, me encanta porque me deja el cabello suave y con mucho brillo. Sin duda alguna es un buen producto y huele riquísimo. 😍😍

Images in this review

Helpful

Report
Translate review to English
Muy bueno la conexión me mejoró mucho cuando lo instale xq yo vivo en una esquina de la casa muy recomendado y fácil de instalar
Muy recomendado
Reviewed in the United States on April 14, 2025
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
Muy bueno la verdad muy recordado me deja el pelo super suave y mi pelo es reseco antes había probado con varias cosas pero este es el q mejor me a funcionado

Read more

Helpful

Report
Translate review to English
Toshiaki Murata
It ok
Reviewed in the United States on October 25, 2024
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
I show video & other sns video
Looks good
But I use my customers it ok resales

Read more

Helpful

Report

Top reviews from other countries

Translate all reviews to English

Fatima Shmali
منتج جيد للغاية 👍🏼👍🏼
Reviewed in Saudi Arabia on April 29, 2025
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase

بكل صراحة المنتج أصلي و يرطب بس خلوه من ١٠-١٥دقيقة عشان افضل نتيجة،أنصح بشرائه

Read more
Report
Translate review to English
lowrance odai
السعودية
Reviewed in Saudi Arabia on February 26, 2025
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
منتج اصلي ايطالي

Read more
Report
Translate review to English
Suleiman Shakkah
جميل جدا
Reviewed in Saudi Arabia on October 31, 2024
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
منتج رائع

Read more
Report
Translate review to English
Jennifer pascua
Very good product
Reviewed in Saudi Arabia on April 14, 2024
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
Buy this if you have very dry and chemically treated hair because of color
Its good to use ince a week to revive your hair

Read more
Report
4almatr
اصلي
Reviewed in Saudi Arabia on June 16, 2024
Size: 16.9 Fl Oz (Pack of 1)Verified Purchase
منتج اصلي وسعره مناسب وبصراحه نفس مفعول اي بلسم مراح اعيد طلبه

Read more
Report
Translate review to English

See more reviews

Disclaimer: While we work to ensure that product information is correct, on occasion manufacturers may alter their ingredient lists. Actual product packaging and materials may contain more and/or different information than that shown on our Web site. We recommend that you do not solely rely on the information presented and that you always read labels, warnings, and directions before using or consuming a product. For additional information about a product, please contact the manufacturer. Content on this site is for reference purposes and is not intended to substitute for advice given by a physician, pharmacist, or other licensed health-care professional. You should not use this information as self-diagnosis or for treating a health problem or disease. Contact your health-care provider immediately if you suspect that you have a medical problem. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease or health condition. Amazon.com assumes no liability for inaccuracies or misstatements about products.

Amazon Prime includes:

Added to cart

Karseell Collagen Hair Treatment 16.9 Oz 500ml Deep Repairs Conditioner Argan Oil Keratin Hair Treatment for Dry Damaged Curly Bleached & All Hair Types

Purchase options and add-ons

About this item

Similar item to consider

Frequently bought together

Frequently purchased items with fast delivery

Sustainability features

Compact by Design (Amazon-developed Certification)

From the brand

Karseell Hair Treatment

Karseell Hair Mask

Collagen Hair Treatment

Hair Conditioner

Karseell Shampoo

Product Description

Product details

Compare with similar items

Videos

Videos for this product

Videos for this product

Videos for this product

Videos for this product

Videos for this product

Videos for this product

Videos for this product

Videos for this product

Videos for this product

Videos for this product