Dual Layer 12-IN Open cell memory foam; 2.5-IN luxurious gel-infused memory foam plus 9.5-IN HD responsive base layer of premium polyurethane foam base, 100% CertiPur-US Certified Foam. Exclusive pressure point relief; conforms to head, neck, shoulder, hips and back; providing spinal alignment for a great nights sleep. Hypoallergenic, allergy suffers can now enjoy this luxury sleeping comfort. Cover is made of knitted fabric which added softness and comfort in contact with skin. Guaranteed it will not go flat. Meets Federal flammability standard CFR1633. Fits any Twin XL size bed.