Serta
Serta Perfect Sleeper X Knox 13.5" Hybrid Firm Mattress
Discover the Serta Perfect Sleeper X Knox Hybrid Mattress, a 13.5-inch firm mattress designed for exceptional spinal alignment and comfort. Featuring a 5 ZoneResponse Design with targeted coils and PerfectConform Memory Foam, it cradles pressure points for rejuvenating sleep. The CoolFeel System and graphite-infused foam actively manage heat, ensuring a cool and comfortable night. Topped with a classic quilted surface for added plushness, this USA-made mattress is adjustable-friendly and built to last.
$999.00
Owner Satisfaction
4.4
/ 5
Category Rank
2083
/ 6148
#2083 in Mattresses
Price vs Category Average
-40%
Below average
Firmness Level
Firm
/ Firm
Who it's for
- Superior Back Support
- Balanced Hybrid Construction
- Enhanced Edge Stability
Who should skip it
- Not Suitable for Side Sleepers
- Potential for Heat Retention
- Heavy and Difficult to Move
Key Specs
Firmness Level
Firm
Mattress Type
Hybrid
Thickness
13.5 inches
Comfort Layer
Memory Foam, Gel Foam
Motion Isolation Level
Good
Adjustable Base Compatible
Yes
Sleep Position Suitability
Back Sleepers, Stomach Sleepers
Warranty
10 Years
Features
- Superior spinal alignment with zoned coils
- Pressure relief with contouring memory foam
- Advanced cooling for comfortable sleep
- Plush quilted top for added comfort
- Designed and built in the USA
- Compatible with adjustable bases
- Minimizes partner disturbance
What customers say
The Serta Perfect Sleeper X Knox 13.5" Hybrid Firm Mattress generally garners a very positive reception, positioning it as a strong contender for consumers prioritizing robust support and durability. Customers frequently laud the hybrid construction, noting that the combination of high-density foam layers and the individually wrapped coil system successfully delivers the deep, unwavering support characteristic of a firm mattress, while still offering enough pressure relief to prevent common discomfort points. This makes it an especially popular choice among back and stomach sleepers who require excellent spinal alignment. Reviewers consistently highlight the minimal motion transfer, a significant benefit for couples, allowing for undisturbed sleep even when a partner shifts. The mattress's substantial 13.5-inch profile contributes to a feeling of luxury and longevity, reinforcing the perception of high quality. However, the primary point of contention revolves around the 'Firm' designation. Many users emphasize that the mattress is *extremely* firm upon arrival, necessitating a significant break-in period, sometimes lasting several weeks, before the comfort layers fully soften. A smaller, but notable, group of side sleepers found the firmness too unforgiving, suggesting this model is best suited for those who truly prefer a very hard sleep surface. While the quality and construction are rarely questioned, the value perception occasionally dips when customers feel the initial firmness is too aggressive for the price point. Overall, the sentiment reflects satisfaction with a high-quality, supportive mattress, provided the buyer understands and desires a truly firm sleeping experience.
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