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Serta

Serta ThermaGel Cooling, Pressure-Relieving Memory Foam Mattress Topper, 2 Inch, California King | 2 inch Cal King gel memory foam mattress topper, ThermaGel cooling, pressure relief, CertiPUR-US, made in USA

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Condition: New
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Availability: In Stock.
Fulfilled by Amazon
Arrives Monday, Aug 24
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Size: California King 83"x71"


Set name: 2 Inch


Features

  • 100% Memory Foam
  • STOP SLEEPING HOT ACROSS YOUR FULL CAL KING BED: Cooling gel-infused memory foam pulls body heat from the entire extended California King sleep surface, keeping both partners cool all night. ThermaGel cooling dissipates heat.
  • PRESSURE RELIEF FOR COUPLES ON A CAL KING: 2 inches of contouring memory foam cushions the hips, shoulders, and lower back across the full Cal King length for back pain relief and restorative sleep. Side, back, and stomach sleepers.
  • SOFTENS A FIRM OR AGING CALIFORNIA KING MATTRESS: This gel memory foam mattress topper adds a plush feel that softens a too-firm Cal King and extends the life of an older mattress.
  • BUILT TO TRUST: CertiPUR-US certified foam, made in the USA, with ventilated, breathable construction. Tested for low VOC emissions, durability, and content safety. Sized 71 x 83 inches to fit standard California King bed frames, platform beds, and adjustable bases.
  • IDEAL FOR PRIMARY BEDROOMS WHERE BOTH PARTNERS NEED COOLER SLEEP: A reliable California King mattress topper for couples. Pair under a Cal King fitted sheet for effortless setup. Add to cart today.

Description

"Dealing with heat buildup or pressure discomfort on your California King mattress? The Serta ThermaGel 2-Inch California King Gel Memory Foam Mattress Topper delivers cooling comfort and targeted pressure relief across the full extended length of your Cal King bed. ThermaGel-infused memory foam actively pulls heat away from the body, maintaining a consistently cooler sleep surface through the night , especially beneficial for hot sleepers or couples sharing a larger bed. The 2-inch foam layer conforms to individual body contours along the full California King length, cushioning the hips, lower back, and shoulders for back pain relief and more restorative sleep. Ventilated, breathable construction supports airflow for all sleep positions. This gel memory foam mattress topper is made in the USA with CertiPUR-US certified foam for trusted safety, durability, and low emissions. Softens a firm or aging Cal King mattress and extends its useful life. Compatible with standard California King bed frames, platform beds, and adjustable bases. Upgrade your California King sleep experience without replacing your mattress. Add to cart and experience the cooling, pressure-relieving comfort of Serta ThermaGel. ThermaGel is a trademark of Leggett & Platt, Inc."

Brand: Serta


Color: Blue


Size: California King 83"x71"


Fabric Type: 100% Memory Foam


Special Feature: Breathable, Cooling, Durable, Premium, Pressure Relief


Brand Name: Serta


Age Range Description: Adult


Model Name: ThermaGel


Number of Items: 1


Manufacturer: Elite Comfort Solutions


UPC: 094325278824


Unit Count: 1 Count


Item Type Name: Serta ThermaGel Memory Foam Mattress Topper


Model Number: 12334


Manufacturer Part Number: 12334


Other Special Features of the Product: Breathable, Cooling, Durable, Premium, Pressure Relief


Closure Type: Pull On


Water Resistance Level: Not Water Resistant


Fabric Type: 100% Memory Foam


Product Care Instructions: Spot Clean Only


Material Type: Memory Foam


Size: California King 83"x71"


Item Display Dimensions: 2 inches


Color: Blue


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Aug 24

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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Top Amazon Reviews

    • Queen that's bigger than a King
Size: Queen 79"x59" Set name: 3 Inch
Review Image by Ashley
Review Image by Ashley
Review Image by Ashley
***Edit 05/09*** I realized after rolling and stuffing the topper back into its original box that the topper I received was for a California King. Make sure before you open this thing the sticker reads the size you purchased. Now I will say I received a replacement the very next day and I was able to sleep on it last night. I am changing my 2 🌟 review to a 5 🌟 because of how quickly they replaced it and being able to sleep on it, it was really comfy and I slept so well. My bed is 9 years old but there isn't anything wrong with it, it's just not as comfortable anymore. My boyfriend always complained My bed was too hard and made his back hurt and he said he slept so much better on this 3" mattress topper. This mattress topper is humongous. I ordered a Queen and once it fluffed out it measured way larger than the Queen measurements listed. It's like 85×75. It measures larger than the King sized measurements. It looks ridiculous on my bed and I would have to fold it over the edges or cut the foam for it to fit properly. I'm going to attempt to fold and roll this thing back up to send it off for a smaller size. I will say when I laid on it with the sheets it did feel soft and cool. Fingers crossed the full sized bed isn't too small. ... show more
Reviewed in the United States on May 7, 2026 by Ashley
    • Doesn't seem to run hot!
Size: King 79"x75" Set name: 3 Inch
Package arrived on time and was well packed. We removed it from paking and removed shipping plastic, then allowed it expand per the instructions. It had no offensive odor at all; in fact it was a pleasant smell if anything. The next day we placed it onto our mattress (it was easy to placeand it stays in place well), put the sheets on, and at bedtime we climbed in. The topper provided an excellent mixture of softness and support. It has not run hot at night and is very pleasant to sleep upon. It appears to be a very durable topper. ... show more
Reviewed in the United States on June 15, 2026 by Mike Oberski
    • Better Than Most Other One's
Size: Twin XL (College Dorm Size) 79"x38" Set name: 2 Inch
I have tried several cushions for my well used recliner. The SertaThermaGel Cooling -Memory foam oneI just bought is the most comfortable one yet. It is not even two inches thick,,but does the job wonderfully without sinking in too much like old car seats. I do put a pillowcase over it for sleeping. It needs a cloth cover. It has a plastic feeling one.It does not slip and I don't always cover it.I would call this one supportive and somewhat cooling ... show more
Reviewed in the United States on June 14, 2026 by Meckanic
    • Like sleeping on a cloud – a perfect refresh for my mattress! ⭐⭐⭐⭐⭐
Size: Full 74"x53" Set name: 3 Inch
I bought this Serta ThermaGel topper (3-inch, Full size) to add some life to an older mattress that was starting to feel a bit too firm and lumpy. I wanted something that would offer pressure relief without making me overheat, and this has been a fantastic upgrade. Pros: Instant Comfort Upgrade: The 3-inch thickness is substantial. You definitely sink into it, but it feels supportive rather than just squishy. It significantly reduced the pressure points on my hips and shoulders. Cooling Effect: I tend to sleep hot, so I was hesitant about memory foam. However, the "ThermaGel" technology actually seems to work. It feels breathable and stays cooler than standard yellow foam toppers I've used in the past. Brand Quality: It’s nice to see it’s "Made in the USA." The foam feels dense and durable, not cheap or flaky. It expanded to its full shape pretty quickly after unboxing. No Slip: The texture of the foam seems to grip the mattress well enough that it doesn't slide around too much under the fitted sheet. Cons/Things to Note: Initial Smell: Like almost all memory foam products, it had a slight "new foam" smell right out of the box. I let it air out for about 24 hours before putting sheets on it, and the smell went away completely. Care: The instructions say "Spot Clean Only," so I highly recommend using a waterproof or thick mattress protector over it just to keep it clean, as you can't throw this in the washing machine. Verdict: If you aren't ready to buy a brand-new mattress but need better sleep quality, this is a very cost-effective solution. It turned a mediocre bed into a luxury feel. ... show more
Reviewed in the United States on December 2, 2025 by DPM
    • Great value Great topper!!
Size: King 79"x75" Set name: 3 Inch
Review Image by TAMMY T
Review Image by TAMMY T
EXACTLY what i wanted. My family bought me a similar Serta topper 5 yrs ago after a major surgery. My matress has seen better days. The first one was very comfortable and I was still using it but my large dog digs at the bed before laying down and did rip it. Honestly, the first one was a little too soft. I had a full open abdominal so those muscles were cut and I have bad joints , so sitting up can be tricky. I found you sink in and had to actually roll to get up. This Serta topper is much more comfortable & much easier to get up from because all though soft, it is firmer. It bounces right back after you get up. . It gives but doesn't make you sink. This helps sleeping when you have joint pain. I didnt feel as hot with it as much as the first either but could just be me. It came in a solid box ,( grandkids LOVE the box with the sheep and large flaps lol) compressed, well wrapped and in a duffle bag. It was fully expanded as soon as I opened it. I didnt notice any smells. This was the best sleep I've had in a long time and at this price I've considered buying an extra when it inevitably rips and wears down but I've read some reviews online that toppers didn't fully expanded after stored a long time. Ill just enjoy this till it dies and replace it then. It was very fast shipping also. I HIGHLY RECOMMEND THIS & WILL buy again! ... show more
Reviewed in the United States on September 27, 2025 by TAMMY T
    • Made my son's dorm bed comfortable
Size: Twin XL (College Dorm Size) 79"x38" Set name: 3 Inch
It's a Serta, need I say more? Made my son's dorm mattress so much more comfortable. He slept very well, didn't over heat in the summer. Held up very well, kept its loft and its ready for his sophomore year
Reviewed in the United States on July 10, 2026 by Humsley
    • Need a mattress pad? This is the one.
Size: Queen 79"x59" Set name: 3 Inch
I like it. I’ve slept way more comfortably since I put it on my bed. Looks nice. I let it air out and sit for a day before putting it on my bed and it doesn’t smell bad at all. Not hot. Seems durable. I rotate my mattress every two weeks and it stays nice.
Reviewed in the United States on June 23, 2026 by Phoenix Gomez
    • I received a used Serta 3in thermal gel topper, very disappointing.
Size: Queen 79"x59" Set name: 3 Inch
Review Image by Gaven
Review Image by Gaven
Review Image by Gaven
I received a used Serta 3 inch thermal gel topper, even though I bought it from new on Amazon. The item came in a Serta zipper round bag, but was not in its original packaging inside zipper bag. When I opened the zipper bag up it was already expanded with very minimal plastic wrap around the sides. There were three dried leaves wrapped in the plastic wrap with the topper. I had to pick the leaves out from the topper. The bottom and top of topper was completely open and exposed, no plastic wrap. I only give it a three star because I received a used one that was unsealed. I don’t know where this one has been. I do have to say the topper is very comfortable and soft yet supportive on my back and hips. Even though I don’t feel any cooling effects, the topper is not hot and doesn’t make me sweaty at night like other foam toppers do. But for the price of $112 on Amazon, I should’ve gotten a brand new one, sealed completely in its original package like I ordered. I’m very disappointed that Amazon would allow something like this to happen, I may not be ordering from Amazon in the future, if this is how they send people used items that are bought and supposed to be brand new. ... show more
Reviewed in the United States on July 14, 2026 by Gaven

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