APEX CORE Gel-Foam Wheelchair CushionsRecommended for patients at risk for pressure ulcers The firm core foundation is made of high density beveled polyethylene to help eliminate hammocking sagging in the middle APEX design features dual density foam layers to provide a soft top entry layer for direct interface with a cooling gel pod and a higher density base layer for support and pressure distribution Breathable stretch removable cover is made of a pressure reducing fabric that promotes