We had used fiberglass; Long long ago, we haven't been using fiberglass any more. You and your family's health is our primary concern and protection. {MATERIAL & CONSTRUCTION}: To improve support and heat dissipation, Molblly 8 inch Cooling-Gel Memory Foam Mattress is designed with THREE layers all-foam system, including 2" memory foam, 1" comfortable layer, and 5" high density base support foam for ultimate comfort. {HEALTH & HYPOALLERGENIC MATTRESS}: The foam has been certified by CertiPUR-US and Oeko-Tex Standard 111 without harmful substances like formaldehyde, mercury, and other heavy metals. {COMFORTABLE & BREATHABLE}: All-foam bed design combined expertise and the best materials with advanced sleep technology. Memory foam conducive to continuous airflow & breathable; skin-friendly fabrics adapt to the environment to keep the mattress surface at the ideal sleeping temperature; Buoyant, no-sink support foams adapt and conform to your body for optimal pressure relief; Specialized foams reduce motion transfer of a partner so your sleep is undisturbed. {EASY SHIPPING & SET-UP}: Mattress is compressed and packaged in a box for shipping, allowing it to easily be delivered to your door and expand to its full lofty shape inside your home. They fit all frames, such as box spring, floor, slatted base, flat platform or adjustable bed, hospital bed. Product Dimensions Twin: 39"L x 75"W x 8"Th ,Full: 54"L x 75"W x 8"Th ,Queen: 60"L x 80"W x 8"Th