The Equalizers multi-component construction an ultra-comfortable viscoelastic memory foam top, a contoured foundation layer for proper positioning of the legs, and an extra soft relief zone for high-risk bony prominences. Three zones of a proprietary, gel-like soft polymer provide added pressure dispersion under the thighs, greater trochanters, and ischial/tailbone region.The cushions moisture-resistant cover has a rugged nylon bottom with a 2-way stretch fabric top and convenient front carry handle. Cover accommodates optional Sling-Fill Base. The Equalizer is available in four standard sizes with an average weight of just 4 pounds.Visco-Elastic Foam Topper: For softness, conformance, comfort and pressure redistributionFirm, Contoured Foundation Layer: Assists in proper positioning of femurs and pelvis.Gel Layer: Three zones of a proprietary gel-like polymer provide added pressure dispersion under the thighs, greater trochanters, and ischial/coccyx region.Soft Ischial Cushion in Base Layer: Extra softness under the most vulnerable bony prominences in sitting.1 Each / Each