The 9" Sierra memory foam mattress is made of 2 layers.

Removable cover:
100% Polyester.

Comfort layer (2 inches):
Polysleep open cell viscoelastic hybrid foam ISO 20743 certified -
Density of 3.0 lb/ft3.

Support layer (7 inches):
Polysleep foam - Density of 1.5 lb/ft3.