Indicates how firm a mattress is on our scale from 1 to 10, where 1 is very soft and 10 ... Some so-called "hybrid" innersprings include one or more levels of foam on top.

The second I laid down on the Serta iSeries 2.0 Hybrid mattress ... bases. The mattress is delivered in its full size (not compressed to ship in a box) and comes with a 10-year limited warranty.

Serta offers a lengthy 120-night trial period, and if you don't like the mattress, you get a full refund. The warranty is 10 years and covers ¾-inch sagging ... Or, choose a hybrid mattress ...

The Mattress Firm Sleep Week sale has exclusive deals through Monday, March 10. Before the 72 ... $391.99 at Mattress Firm Serta iSeries 2.0 Hybrid 1000 12-Inch Medium Mattress, Queen Get 33% ...