Modern Sleep 4-1/2" Sofa Bed Memory Foam Mattress. Replacement Sofa Bed Mattresses. Memory Foam Mattress SALE! This Plush Yet Durable Sofa Bed Mattress Will Give Your Visitors a Comfortable Nights Sleep. (Twin: 72"L x 33"W x 4.5"H) Pressure-relieving design Alleviates pressure points Aligns spine for optimal sleep Folds inside couch and returns to shape when pulled out 2.5