FATHOM Medium 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 to apply
- – 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
90-day returns
Learn more
90-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:
Only 4 left in stock, order soon!
Arrives
Thursday, Jun 4
Recently Viewed
Size: King (U.S. Standard)
Style: 12 Inch
Pattern Name: Medium
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
Item Firmness Description: Medium
Top Style: Gel Top
Cover Material: Polyester
Number of Layers: 4.0
Fill Material: Gel Memory Foam, Memory Foam
Special Feature: Breathable, Durable, Low Motion Transfer, Pressure Relief, Temperature Regulating
Color: Medium
Product Dimensions: 80 x 76 x 12 inches
Item Weight: 80.8 pounds
Manufacturer: FATHOM
Item model number: Medium 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:
Thursday, Jun 4
Yes, absolutely! You may return this product for a full refund within 90 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: 12 Inch
Pattern Name: Medium
I recently upgraded to a 12-inch queen foam mattress, and it has truly transformed my sleep experience. From the moment I first lay down, I could tell this mattress was something special. What stands out most is the perfect balance of support and comfort. The foam is firm enough to keep my spine aligned — my lower back pain has noticeably improved — yet soft enough to cradle pressure points and relieve tension. I’ve woken up feeling refreshed and pain-free, which hasn’t happened in years with my old mattress. Another highlight is how cool and breathable this mattress sleeps. Even on warm nights, I stay comfortable without overheating. The foam layers are designed to promote airflow, so I never wake up sweaty like I used to with other memory foam beds. Comfort-wise, it’s truly luxurious. It gently contours to your body, giving that “just right” feeling — not too stiff, not too plush. Whether I’m on my back, side, or stomach, it adapts perfectly and feels supportive without being restrictive. In short, if you’re looking for a high-quality queen mattress that’s excellent for back support, incredibly comfortable, and refreshingly cool, this 12-inch foam model is a stellar choice. It’s been one of the best sleep investments I’ve ever made — I wake up happier, healthier, and ready to take on the day!
...
show more
Reviewed in the United States on January 5, 2026 by Dayana
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
This Fathom Medium Queen Mattress is a 10-inch memory foam mattress designed for comfort, support, and cooler sleep. It features gel-infused foam that helps regulate temperature while relieving back pain and pressure points. The medium firmness offers a balanced feel, suitable for most sleeping positions. Conveniently packaged as a bed-in-a-box, it is easy to set up. The removable cover is fiberglass-free for safer use. CertiPUR-US certified materials ensure durability and low emissions. Ideal for everyday comfort, this mattress combines support, cooling, and quality for restful, healthy sleep.
...
show more
Reviewed in the United States on January 11, 2026 by Juanderlie Josema Juanderlie Josema
Size: Queen (U.S. Standard)
Style: 12 Inch
Pattern Name: Medium
It provides good support and has helped reduce back pain. There is no uncomfortable sinking, and the mattress maintains its shape well. Heat retention is minimal, so it stays comfortable throughout the night. Motion transfer is also very low, making it a great choice for restful sleep. Overall, excellent quality and value.
...
show more
Reviewed in the United States on January 17, 2026 by jaqueline torres
Size: Queen (U.S. Standard)
Style: 12 Inch
Pattern Name: Medium
I’ve been sleeping on the FATHOM Medium Queen 12-Inch Memory Foam Mattress for several weeks now, and it has made a noticeable difference in my sleep quality. The medium firmness is a great balance between support and comfort. It contours nicely to the body without that “sinking” feeling, and my lower back feels much more supported compared to my old mattress. I wake up with far less stiffness and soreness. The mattress stays surprisingly cool throughout the night, even during warmer evenings. I also really appreciate the removable, fiberglass-free cover, which feels soft, breathable, and is easy to clean. Setup was simple, right out of the box and fully expanded within a day. No strong chemical smell, just a very faint “new mattress” scent that disappeared quickly.
...
show more
Reviewed in the United States on January 14, 2026 by Tracy Truong
Size: Queen (U.S. Standard)
Style: 12 Inch
Pattern Name: Medium
I’m really impressed with this mattress. It’s extremely comfortable and surprisingly spacious, perfect for relaxing or sleeping without feeling crowded. The top layer feels soft and plush, while the lower layers provide great support, so you get the perfect balance of comfort and firmness. Since I started using it, I’ve been waking up without any back pain and feeling much more rested. It doesn’t sink, it doesn’t wobble, and it keeps its shape beautifully. Even with two people on the bed, it feels stable and roomy. The quality is excellent as well — the materials feel premium, and the overall look is very clean and modern. This mattress works great
...
show more
Reviewed in the United States on January 26, 2026 by jeff
Size: King (U.S. Standard)
Style: 14 Inch
Pattern Name: Medium
Super comfy, cool and no smells. A heads up that it can take up to 72 hours to attain actual mattress height.
Reviewed in the United States on January 31, 2026 by m ledwell
Size: Queen (U.S. Standard)
Style: 10 Inch
Pattern Name: Medium
Great mattress for the price! It provides solid support without sinking and has noticeably helped reduce my back pain. The medium firmness is comfortable, it holds its shape well, and it doesn’t trap heat, so I stay cool all night. Motion transfer is minimal, which is a big plus. Easy setup and good thickness, fits perfect. definitely a great value.
...
show more
Reviewed in the United States on January 29, 2026 by Adib b
Size: Queen (U.S. Standard)
Style: 12 Inch
Pattern Name: Medium
This mattress is so comfortable! You can literally feel yourself sink into it. It’s soft but still supportive. Set up was super easy, just cut the wrapping; it unrolled and expanded on its own. It was so flat when I received it, but it expanded to 12 inch thick. It didn’t have a chemical smell to it like lot of new furniture, just a clean scent. The material feels like it will hold up for a long time. Very satisfied with my purchase!
...
show more
Reviewed in the United States on January 17, 2026 by Brandy Nicole Brandy Nicole