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4.6 | 73 Reviews

Perfect Sleeper X Knox 13.75" Hybrid Plush Mattress -California King

Perfect Sleeper X

Features

  • Our 5 ZoneResponse™ Design combines coils and contouring memory foam for full body spinal alignment
  • Our PerfectConform™ Memory Foam contours and cradles your pressure points for rejuvenating sleep
  • CoolFeel™ System - Cooling technology keeps you comfortable throughout the the night
  • CertiPUR-US® Certified

Quick Specs

  • Brand: SERTA
  • Line: Perfect Sleeper X
  • Type: Tight Top
  • Width: 13.75"
  • Height: 72"
  • Depth: 84"

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Experience premium support and perfect sleep with our new Serta® Quilted Perfect Sleeper X™ Collection. Our 5 ZoneResponse™ Design is comprised of Perfect Conform™ Memory Foam paired with 5-zoned coils for full-body alignment. Sleep comfortably cool throughout the night with cooling technology and graphite-infused memory foam designed to redistribute heat away from your body. A quilted top offers a classic feel and added layer of plush foam. Xtraordinary sleep is possible, with Serta® Quilted Perfect Sleeper X™.

Features

  • Our 5 ZoneResponse™ Design combines coils and contouring memory foam for full body spinal alignment
  • Our PerfectConform™ Memory Foam contours and cradles your pressure points for rejuvenating sleep
  • CoolFeel™ System - Cooling technology keeps you comfortable throughout the the night
  • CertiPUR-US® Certified
  • Designed and Built in USA
  • Adjustable Friendly
  • 10 Year Warranty
  • Your new mattress may initially feel firmer than expected. Please allow up to 60 days to acclimate to your new mattress as it naturally adjusts to contour, comfort, and support you best
  • Plush - Great for side sleepers for extra comfort at the shoulders, hips and lower back
  • Premium memory foam is temperature-sensitive; it may feel firmer in cooler temperatures and softer in warmer ones. For your preferred comfort, please allow several hours for your memory foam mattress to adjust to the room's temperature
Brand Serta
Manufacturer Name Serta Simmons Bedding LLC
UPC 198167021355
Computed Mattress Size Cal King
Country of Manufacture USA
Assembled in USA? Yes
Computed Product Type One Sided Mattress
Product Category Mattress
Family Name Perfect Sleeper X
SubFamily Name Knox
Mattress Top Type Tight Top
Mattress Type Hybrid
Product Type Mattress
Year of Launch 2024
Dealer Line National Line
Layer 1 Material Serta PillowSoft HD Foam
Layer 1 Thickness (in) 1.25
Layer 2 Material PillowSoft Aire
Layer 2 Thickness (in) 1
Layer 3 Material Cushion Gel Foam
Layer 3 Thickness (in) 1.5
Layer 4 Material PerfectConform Graphite Memory Foam
Layer 4 Thickness (in) 1
Layer 5 Material 5 ZoneActive Hybrid Design
Layer 5 Thickness (in) 8
Layer 6 Material Support Foam
Layer 6 Thickness (in) 1
Base Layer Material 5 ZoneActive Coil Unit
Product Depth (in) 83.5
Product Height (in) 13.75
Product Width (in) 72
Shipping Depth (in) 72.5
Shipping Height (in) 14.25
Shipping Width (in) 84
Product Weight (lb) 124.03
Shipping Weight (lb) 74
Adjustable Base Compatible? Yes
Antimicrobial? Yes
Breathable Construction? Yes
Coil Count 952
Coil Density 1203
Coil Type Pocketed Coil
Coil Gauge 0.068"/0.074"
Cooling Technology? Phase change material
Edge Support? Yes
Foam Infusion? Graphite
Handles Included? Yes
Is Mattress 2 Sided? No
Latex Free? Yes
Mattress Comfort Level Plush
Mattress Cover Design Floral
Mattress Cover Stitch Design Floral
Mattress In A Box? No
Moisture-Wicking? Yes
Pillow Top? No
Product Accent Color Light Blue
Product Cubes 52.07
Quilted Cover? Yes
Side Color Dark Blue
Top Cover Color Black
Zipper Cover Machine Washable? N/A
Zipper Cover? No
Product Warranty Length 10
Does it Ship in a box Yes

Quick Specs


  • Manufacturer

  • Brand: SERTA
  • Line: Perfect Sleeper X

  • Appearance

  • Type: Tight Top

  • Dimensions

  • Width: 13.75"
  • Height: 72"
  • Depth: 84"
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Professional delivery and installation is available for every product we sell. We would be happy to coordinate delivery and installation for you.

Extended warranties are usually very inexpensive and can save you thousands in the future. It's simple and inexpensive to purchase extended warranties and one of the smartest ways to protect your investment.

Mattresses can be large, heavy and expensive. You probably don't have the special tools or expertise needed to fix them in a crisis. If you can spare a few thousand dollars without batting an eyelash for new bedding should they break tomorrow, don't buy a warranty. But if you're like most of us, protect yourself by purchasing inexpensive extended warranties when you buy a new product and save yourself big money in the long run.

4.6 out of 5

89% of reviewers recommend this product.

4 Stars

Good

Michael B 11/1/2025

Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Comfy

Gary E 10/25/2025

No more back aches
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Great!

Gary E 10/19/2025

Comfy & good night's rest!
Originally posted on www.serta.com

Yes, I recommend this product

3 Stars

Disappointing

Teresa H 10/15/2025

Already showing body imprints. Not really "cool" sleeping. It's just ok.
Originally posted on www.serta.com

No, I do not recommend this product

3 Stars

Adjustable bed

Barbara E 10/13/2025

I like the bed but unhappy that I cannot use my head board and it is difficult to keep the top sheet secured.
Originally posted on www.serta.com

No, I do not recommend this product

5 Stars

Comfort!!

Normand G 9/29/2025

Very comfortable mattress!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Great mattress

Stephen m M 9/28/2025

Comfortable and supportive!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Extremely comfortable

Pam C 9/20/2025

This mattress is so comfortable. It gives to your body but also supportive.
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Saved my back

Debbe H 9/19/2025

I have a lot of health issues with my back and haven't been able to find a mattress that is comfortable until now. Thank you so much.
Originally posted on www.serta.com

Yes, I recommend this product

4 Stars

New Mattress

Nina T 9/18/2025

So far it's comfy
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Great quality

Maha A 9/18/2025

Comfy and nice matters
Originally posted on www.serta.com

Yes, I recommend this product

4 Stars

New Mattress

Arthur T 9/18/2025

So star, so good!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Best sleep ever!

Sherry S 9/14/2025

Very comfortable and supportive! Woke up after the first nights sleep with no up pain!!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

New mattress we love it

Kent S 8/25/2025

Very nice and supportive
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

So far so good

Linda S 8/14/2025

Having slept on our new Serta Perfect Sleeper X Hybrid Knox Plush Cal King for two nights has been wonderful. Supportive and comfortable for much needed good night sleep.
Originally posted on www.serta.com

Yes, I recommend this product

3 Stars

So so

Patricia B 8/11/2025

Seems to stay indented where I sleep. Didn't think I would have that with such an expensive mattress. But seems to be comfortable.
Originally posted on www.serta.com

No, I do not recommend this product

5 Stars

Plush

Jason S 8/3/2025

Mattress is plush and comfy. And a great fabric coloration.
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

So comfy

Marisol R 7/11/2025

Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Serra Mattress

Deborah T 7/5/2025

Perfect depth and comfortable
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Comfortable

Kimberly C 7/1/2025

Originally posted on www.serta.com

Yes, I recommend this product

4 Stars

Great mattress

Adam C 6/14/2025

This mattress starts out firm at first but after a few nights sleep is very comfortable. I normally sleep on my back and it's very supportive of them mid to low back and cradled your body!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Extremely comfortable

Edna B 6/6/2025

Comforting for a very relaxing sleep.
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Excellent Mattress

Erika P 6/5/2025

So very comfortable and cool!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

The best sleep in years

Susan T 5/20/2025

I had my other mattress for 15 years, and it was great until the last week. I knew I had to replace it. I went to Mattress Peddler as I had been there when friends mattress shopping and was impressed with the professionalism and kindness of the owner. I love the mattress I purchased. Just the right firmness. I am so happy
Originally posted on www.serta.com

Yes, I recommend this product

4 Stars

Great sleep

Douglas E 5/20/2025

So glad we bought this one. Sleep is so much better.
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

New mattress and box spring

James K 5/14/2025

Seems to be a great mattress
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

"It's good, I like it!"

Jeremy H 4/19/2025

These are the words of the wisest, smartest, and most beautiful person in the world: My Wife. Passes the wife test, passes my test.
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

GREAT MATRESS !!

CA2025 4/19/2025

Perfect firmness for both my wife and my needs. Slept like I didn't have kids waking me up every few hours again.
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Very comfortable.

Dan24 4/7/2025

I'm very happy with my new mattress. I've been using it for a few weeks now, and my body feels more rusted and less pain when waking up.
Originally posted on www.serta.com

Yes, I recommend this product

1 Stars

Take a pass on the whole thing

FredTX 4/6/2025

Extremely poor product and customer service. RXO Logistics - if a company uses them for last mile move along to someone else - save yourself the hassle. Canceled my delivery at the last minute - unable to provide any information on whereabouts of the mattress. Wound up canceling the order. To make matters worse, I ordered the mattress from a retailer and am now returning it. Hard as a rock! Nothing plush about it including the pillow top. Make another selection.
Originally posted on www.serta.com

No, I do not recommend this product

5 Stars

New mattress

Cleveland G 4/3/2025

Originally posted on www.serta.com

Yes, I recommend this product

3 Stars

Firm

Mel V 4/2/2025

Don't have any issues with the bed or service. Customers should know this bed is very firm.
Originally posted on www.serta.com

No, I do not recommend this product

5 Stars

Exceptional comfort

Ceren O 3/27/2025

Nice cooling down at night
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Happy Happy Happy

Cynthia D 3/26/2025

Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

A Perfect Balance of Comfort and Support!

DrJLD 3/25/2025

We absolutely love our Serta mattress! At first, it felt a bit stiff, but after a few days of breaking it in, it became incredibly comfortable. We made the switch from our previous pillow top options because they kept breaking down too quickly, and we're so pleased with our decision. This mattress provides great support and feels much more durable. Overall, we couldn't be happier with our purchase!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Restful sleep

Margaret M 3/22/2025

Our mattress was 20 years old. This mattress is so comfy. Not too soft not too hard. Jyst right.
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Perfect!

Keith L 3/22/2025

I was looking for more support something not too hard and not too soft and I settled for the plush and it's perfect!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Comfortable

Jason S 3/22/2025

Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Comfortable

Bryan F 3/14/2025

Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Fantastic support!

Michelle S 3/9/2025

This mattress is so comfortable! Perfect amount of softness on the top to support my curves with great firm support beneath. I am just giddy to climb into bed each night. I don't know why I didn't buy a new mattress sooner. I had no idea what I was missing!
Originally posted on www.serta.com

Yes, I recommend this product

3 Stars

Doesn't feel like it did in the store

Wayman T 2/22/2025

Hoping it will soften soon
Originally posted on www.serta.com

No, I do not recommend this product

1 Stars

Bad quality

Mattori 2/22/2025

I just started sleeping on this mattress and it has a horrible bubble in the middle. This is the cool calming queen mattress. It's a replacement for a different mattress from serta and it only lasted 6 months before the sides started caving in. I will never buy a serta mattress again.
Originally posted on www.serta.com

No, I do not recommend this product

5 Stars

Comfortable!

Marcy M 2/17/2025

Definitely comfy!
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Excellent!

Kimberly A 2/16/2025

Great first nights sleep!
Originally posted on www.serta.com

Yes, I recommend this product

1 Stars

What a nightmare

Wheresmymattress 2/13/2025

Hard to review a mattress when it has yet to arrive. Just the fact they asked me to review the mattress means they have no idea I don't have it yet. The Shipping company Serta uses lost the first mattress. Had to wait for Serta to manufacture another one. Now the delivery company keeps pushing delivery dates back on us. 2 months now
Originally posted on www.serta.com

No, I do not recommend this product

5 Stars

Emankcin 1/31/2025

Very comfortable mattress for me. Firm but not too firm. No more back ache.
Originally posted on www.serta.com

Yes, I recommend this product

4 Stars

Getting use to it

Josefina P 1/21/2025

Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

our mattress

Andrea D 1/20/2025

Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Excellent mattress

David K 1/19/2025

Very comfortable and supportive. Provide a great nights sleep
Originally posted on www.serta.com

Yes, I recommend this product

5 Stars

Great

Patrick L 1/15/2025

So comfortable love it
Originally posted on www.serta.com

Yes, I recommend this product