Specification and editorial comparison · lab measurements not available
Updated October 2026
Category
Plank Firm
Casper The One
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
Plank Firm
Casper The One
Type
All-Foam
All-Foam
Firmness
9/10
6.5/10
Height
10 inches
11 inches
Shipping
Free shipping
Free shipping & returns
Model specifications are catalog reference details, not instrumented measurements. Confirm the exact configuration and current seller terms.
Key Advantages
Why Choose Plank Firm
- Flippable — firm and extra-firm surfaces in one mattress
- Excellent for stomach sleepers
- Great spinal alignment
Why Choose Casper The One
- Lowest price in the current Casper lineup
- Zoned support keeps hips from sinking
- Class-leading motion isolation for couples