FATHOM Firm King Mattress 12 Inch Memory Foam Mattress King Size Bed in a Box for Back Pain Relief and Cool Sleep with Gel Foam and Removeable Fiberglass Free Cover, CertiPUR-US Certified
Condition: New
Buy Now, Pay Later
As low as
/ mo
Learn more
- – Up to 36-month term if approved
- – No impact on credit
- – Instant approval decision
- – Secure and straightforward checkout
Ready to go? Add this product to your cart and select a plan during checkout.
Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Apple Pay, and PayTomorrow. No-credit-needed leasing options through Acima may also be available at checkout.
Learn more about financing & leasing here.
Selected Option
Free shipping on this product
100-day returns
Learn more
100-day refund / replacement
To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
Availability:
In Stock.
Arrives
Friday, Nov 21
Recently Viewed
![4 Pack Screen Protector for iPhone 13 Pro Max[6.7 inches] With 2 Pack Camera Lens Protector, [Drop Protection] 9H Hardness Scratch Resistant Tempered Glass Film, Easy to install - HD Clear](https://m.media-amazon.com/images/I/71ZqJNUsR4L._AC_US500_.jpg)
Size: King (U.S. Standard)
Style: 12 Inch
Pattern Name: Firm
Features
- Advanced Cooling Comfort: The AeroFusion gel memory foam mattress ensures exceptional breathability and heat dissipation, adapting precisely to your bodys contours while resisting temperature sensitivity. Enjoy cool, cradling comfort no matter the season.
- Premium, Thoughtful Design: Wrapped in a soft, geometric-patterned jacquard fabric with stylish light gray graphene yarn borders. The fiberglass-free mattress cover is not only elegant but functional, featuring a zipper for easy removal and cleaning.
- Motion Isolation Technology: Dynamic memory foam mattress contours to your bodys unique curves, filling gaps to support optimal spinal alignment while effectively lowering motion transfer and noise, ensuring a serene and undisturbed sleep environment where everyone wakes up refreshed, ideal for couples and kids.
- Certified Safe Material: Crafted in the USA with CertiPUR-US foams and globally sourced Oeko-Tex certified fabrics, our king mattress is free from harmful substances. Backed with a 10-year protection, Fathom mattress is designed to promote spinal health and long-term durability for a healthy lifestyle.
- Effortless Setup: The Fathom mattress in a box is vacuum-packed, compressed and rolled for easy movement and installation. Simply open and unroll your memory foam mattress, then enjoy it within 72 hours for full expansion.
Brand: FATHOM
Size: King (U.S. Standard)
Product Dimensions: 80"L x 76"W x 12"Th
Top Style: Gel Top
Cover Material: Polyester
Number of Layers: 3.0
Fill Material: Gel Memory Foam, Memory Foam
Special Feature: Breathable, Durable, Low Motion Transfer, Pressure Relief, Temperature Regulating
Color: Firm
Model Name: Fathom Firm 12" K
Product Dimensions: 80 x 76 x 12 inches
Item Weight: 85 pounds
Manufacturer: FATHOM
Item model number: Firm 12 K
Date First Available: April 23, 2025
Age Range Description: Adult
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Friday, Nov 21
Yes, absolutely! You may return this product for a full refund within 100 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
- Klarna Financing
- Affirm Pay in 4
- Affirm Financing
- Afterpay Financing
- PayTomorrow Financing
- Financing through Apple Pay
Learn more about financing & leasing here.
Similar Products
Top Amazon Reviews
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
I bought this 10-inch memory foam mattress for the spare bedroom so our older kids have a comfortable place to sleep when they visit. It arrived quickly, was easy to unpack, and to my surprise there was no chemical smell at all—a big plus compared to other memory foam mattresses I’ve tried. The mattress expanded to full size within a couple of hours and feels supportive yet cozy. Our kids have already stayed over a few times and commented on how well they slept. It’s firm enough to provide good back support but still has that soft memory foam hug. For the price, quality, and simple setup, this mattress is a perfect choice for a guest room. I’m happy knowing our visitors have a great night’s sleep when they come to stay.
...
show more
Reviewed in the United States on September 29, 2025 by Deborah Cosgrove Deborah Cosgrove
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
The FATHOM Medium Queen Mattress (10 Inch Memory Foam) is amazing! It arrived perfectly packaged in a compact box and expanded quickly after opening. The mattress feels just the right balance of soft and firm — super comfortable for both back and side sleepers. The gel memory foam keeps it nice and cool throughout the night, and I’ve noticed a big improvement in my back pain since switching to it. The removable fiberglass-free cover is a huge plus for peace of mind and easy cleaning. Overall, a high-quality, comfortable, and affordable mattress that truly delivers on its promises.
...
show more
Reviewed in the United States on October 5, 2025 by Rachana Rimal
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
I’ve been sleeping on the mattress for a while now, and it’s been great. The gel memory foam keeps me cool at night, and the mattress adjusts well to my body, which really helps with back pain. The cover is soft, removable, and easy to clean, and I like that it’s fiberglass-free. Motion isolation is excellent — I don’t feel movement when my husband turns over, which makes sleep much more restful. It feels well-made, supportive, and comfortable without being too soft. Overall a high-quality mattress at a good price that has improved my sleep.
...
show more
Reviewed in the United States on September 19, 2025 by Halyna
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
This mattress is a great choice for anyone looking for comfort and support! It arrived quickly, was super easy to set up, and expanded to queen size in just a few hours. The firmness feels perfect and comfortable yet supportive for however you sleep. I love the cooling gel foam, which helps keep me cool at night. After using it for a few days, I’ve noticed fewer aches and better sleep quality. For the price, it feels just as good as some of the more expensive options. Overall, I’m really happy with it! The quality is so nice and great I highly recommend it So I replace mattress every year If it lasts long I’ll buy more in future for my other beds
...
show more
Reviewed in the United States on September 26, 2025 by Samantha Ross
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
I was nervous ordering a mattress online, but this one exceeded all expectations. It arrived quickly, expanded perfectly, and the quality is excellent. The medium firmness offers just the right balance—supportive without being too hard—and it really helps relieve my back pain. The gel memory foam keeps me cool at night, and the soft, breathable, removable cover is easy to clean and fiberglass-free, which I appreciate. Motion isolation is great; I don’t feel my partner moving, so my sleep is much more restful. The mattress feels durable and stable even with daily use and kids jumping on it. For the price, it’s an incredible value and feels comparable to much more expensive brands. Highly recommend for anyone wanting comfort, support, and cool sleep!
...
show more
Reviewed in the United States on September 26, 2025 by Azim Hossain
Size: Full
Style: 10 Inch
Pattern Name: Medium
Super soft and easy to unpack. I’m not completely sure it’s as full as it should be. It seems thin to me. I will say there were no harsh chemical smells. I am slightly disappointed that it’s not thicker. I bought the 10 inch version for the kid. I will end of replacing with a thicker mattress eventually. It is comfortable though.
...
show more
Reviewed in the United States on September 28, 2025 by JL
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
Super comfy and keeps cool all night! The memory foam feels supportive without being too firm, and I love that it doesn’t get hot. Hardly notice any movement when my partner rolls over. The cover looks nice and can be removed for cleaning, which is a big plus. Setup was easy—just unrolled it and let it expand. Definitely worth it!
...
show more
Reviewed in the United States on September 18, 2025 by Musa
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
I absolutely love this queen mattress! From the very first night, I could tell the difference . It’s the perfect balance of comfort and support. The cushioning feels soft yet firm enough to keep my back aligned, and I wake up feeling rested without any aches or stiffness. The quality is excellent, and it looks and feels like a high-end product. It also stays cool throughout the night, which has made a big difference for my sleep. I couldn’t be happier with this purchase — definitely worth every penny! Highly recommend to anyone looking for a comfortable, durable, and supportive queen mattress
...
show more
Reviewed in the United States on October 12, 2025 by Jung