Mattress Firm Twin Xl material description 1.Nine-zone spring bag  2.3E coconut fiber 3.Cashmere knitted fabric This Mattress Relatively hard, spine protection (about 22cm thick) Feature: Applicable for children, the elderly, and adults with poor waist. The mattress is relatively hard to protect the spine. 3E coconut fiber mattress is compressed from natural coconut fiber under high temperature, no formaldehyde, giving you healthy sleep.