Dynarex | DynaRest Gel Foam Mattress OverlayDynarex DynaRest Gel Foam Mattress Overlay Pressure Relief, Bed Sore Prevention, Fluid Resistant Comfort for Patients The Dynarex DynaRest Gel Foam Mattress Overlay, designed to provide superior comfort and pressure relief for patients at risk of developing pressure wounds or bed sores. This premium mattress overlay features gel infused bladders encased in high density foam, which work together to evenly distribute weight and reduce pressure points.