Specification and editorial comparison · lab measurements not available
Updated October 2026
Category
Saatva RX
Serta iSeries NXG 4500 Ultra Plush Foam
Comfort
Not lab tested
Not lab tested
Support
Not lab tested
Not lab tested
Cooling
Not lab tested
Not lab tested
Edge Support
Not lab tested
Not lab tested
Motion Isolation
Not lab tested
Not lab tested
Durability
Not lab tested
Not lab tested
Value
Not lab tested
Not lab tested
Blank cells mean that model has not completed our instrumented lab protocol, so we publish no measured score for it. We never estimate a number we have not recorded.
Quick Specs Comparison
Spec
Saatva RX
Serta iSeries NXG 4500 Ultra Plush Foam
Type
Luxury Hybrid
Memory Foam
Firmness
3.5/10
3.5/10
Height
15 inches
Varies by comfort level
Shipping
Free white glove delivery
Free shipping
Model specifications are catalog reference details, not instrumented measurements. Confirm the exact configuration and current seller terms.
Key Advantages
Why Choose Saatva RX
- Specifically engineered for chronic pain conditions (sciatica, arthritis, scoliosis)
- Patented Lumbar Zone® quilting for targeted spinal alignment
- Rx Wave-Tech® 5-zone pressure relief system
Why Choose Serta iSeries NXG 4500 Ultra Plush Foam
- Genuinely plush — deep shoulder and hip relief
- Best-in-line motion isolation
- Ultimate Edge keeps a plush foam bed from collapsing at the rail