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FATHOM

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

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Availability: In Stock.
Fulfilled by Amazon
Arrives Friday, Aug 14
Order within 8 hours and 36 minutes
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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.

Description

At Fathom, we believe true wellness starts with truly deep sleep. We're dedicated to helping you fathom the depths of restorative rest.

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


Fill Material: Gel Memory Foam, Memory Foam


Weight Limit: 750 pounds


Special Feature: Breathable, Durable, Low Motion Transfer, Pressure Relief, Temperature Regulating


Item Firmness Description: Medium


Number of Layers: 4


Weight Capacity Maximum: 750 pounds


Additional Features: Breathable, Durable, Low Motion Transfer, Pressure Relief, Temperature Regulating


Construction Type: Memory Foam


Size: King (U.S. Standard)


Item Dimensions L x W x Thickness: 80"L x 76"W x 12"Th


Item Thickness: 12 inches


Item Depth: 12 inches


Item Dimensions: 80 x 76 x 12 inches


Cover Material: Polyester


Fill Material: Gel Memory Foam, Memory Foam


Mattress Comfort Layer Material: Comfort Foam, Gel Memory Foam


Material Type: Gel Foam, Memory Foam


top-style: Gel Top


Color: Medium


Style Name: 12 Inch


Brand Name: FATHOM


Model Name: Fathom Medium 12" K


Product Benefits: Back Pain Relief, Improves Sleep, Pressure Relief, Reduces Toss & Turn, Stress Relief


Model Number: Medium 12 K


UPC: 840418683866


Number of Items: 1


Mattress Type: Standard Mattress


Number of Packs: 1


Manufacturer: FATHOM


Unit Count: 1 Count


Age Range Description: Adult


Included Components: Memory Foam


Item Type Name: Bed Mattress Conventional


Manufacturer Part Number: FA12KMDT


Set Name: Fathom Medium


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Friday, Aug 14

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.

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Similar Products

Top Amazon Reviews

    • Great Balance of Comfort and Support
Size: Queen (U.S. Standard) Style: 12 Inch Pattern Name: Medium
Review Image by Mallikarjun
Review Image by Mallikarjun
I’ve been using this mattress for a while now, and I’m really happy with the comfort it provides. It has a nice balance of softness and support, so I wake up feeling much more refreshed. The gel memory foam stays comfortable throughout the night and doesn’t trap too much heat. I also like that the cover is removable and the mattress is fiberglass-free, which gives me extra peace of mind. Overall, it’s a great value for the price, and I’d definitely recommend it to anyone looking for a comfortable, supportive mattress. ... show more
Reviewed in the United States on August 8, 2026 by Mallikarjun
    • Wow
Size: Queen (U.S. Standard) Style: 12 Inch Pattern Name: Medium
I was a little nervous since i have never purchased a bed in a box before. The delivery was amazing and it got to my door 4 days soon then I thought. The set up was super easy and quick.the mattress inflated within a few hours. And it looks like a top dollar luxury mattress for less than 1/2 the price. I ordered the medium softness and I couldn’t be more pleased. First night in years I wasn’t tossing and turning. So comfortable I fell asleep with in minutes. The mattress is soft and supportive without sinking in. Very well made. Would recommend to anyone looking for a great night sleep without breaking the bank ... show more
Reviewed in the United States on March 28, 2026 by charlene ailes
    • Comfy and breathable
Size: Queen (U.S. Standard) Style: 12 Inch Pattern Name: Medium
Bought this as the old mattress was taking shape from one side. This is turned out to be a really nice mattress. It is soft but firm at the same time, easily able to expand after opening and does not smell much. I highly recommend as for the pricepoint its great.
Reviewed in the United States on July 26, 2026 by Manthan Gajjar
    • SATISFIED
Size: Queen (U.S. Standard) Style: 12 Inch Pattern Name: Medium
Review Image by Idialu Deborah
This mattress is incredibly cozy and comfortable. It provides great support while still feeling soft and relaxing. The memory foam gently conforms to my body and helps me sleep comfortably throughout the night. I also love that it stays cool and doesn’t trap too much heat. The removable cover is a nice bonus, and I feel good knowing it is fiberglass-free and CertiPUR-US certified. Overall, it has made my bed feel much more comfortable, and I’m very happy with this mattress. ... show more
Reviewed in the United States on August 3, 2026 by Idialu Deborah
    • Love the mattress just one issue
Size: Queen (U.S. Standard) Style: 10 Inch Pattern Name: Medium
It’s good, it very comfortable and I love how I feel like I’m sleeping on clouds. The temperature was very cool when I got it but when putting on a comforter it goes away. It doesn’t cause me to sink in too deep which I like. It easy to get onto the bed frame and it looks so clean when you first got it. My only complaint is that I think the sink caused my feet to be numb a bit or ache. ... show more
Reviewed in the United States on July 5, 2026 by Amazon Customer
    • Great mattress in every way.
Size: King (U.S. Standard) Style: 12 Inch Pattern Name: Medium
Defiantly Medium firmness. Sitting it seems soft however laying on it is quite comfortable and a medium firmness telling me that it supports pressure points like hips and shoulders without contorting the body. The mattress took about 48hours to dissipate a mild odor while expanding. I set up a fan to blow across it. Very satisfied. This is for an occasional use for visitors but I would love it as my own and I have an original Temperpedic. ... show more
Reviewed in the United States on July 22, 2026 by Kindle Customer
    • Great Value and Comfort
Size: Twin XL Style: 12 Inch Pattern Name: Medium
For the price, this 12-inch memory foam mattress is an excellent deal. The quality is impressive for a "bed in a box," and the Twin XL size is perfect for tighter spaces or college dorms. The medium firmness offers a nice balance—it’s supportive enough for back alignment but still has that classic memory foam "hug" for pressure relief. It also stays surprisingly cool throughout the night. If you're looking for a comfortable, budget-friendly upgrade that doesn't feel cheap, this is a solid investment. ... show more
Reviewed in the United States on May 15, 2026 by Michelle
    • Comfortable, Supportive, and Great for a Cool Night’s Sleep
Size: Queen (U.S. Standard) Style: 12 Inch Pattern Name: Medium
I’ve been sleeping on this mattress for a little while now, and I’m really happy with it. It arrived compressed in a box, and setup was easy. It expanded quickly and was ready to use within a day. The mattress has a nice balance of softness and support. The memory foam contours to my body without making me feel like I’m sinking in too much. I usually wake up with less back discomfort, and it provides great support whether I’m sleeping on my back or side. ... show more
Reviewed in the United States on July 18, 2026 by Amazon Customer

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