Drive Medical Sierra Gel Overlay, 34" x 4" Optimal environment for the treatment and prevention of pressure ulcers One-Piece construction requires no assembly; Elastic corner straps to secure overlay to mattress Easy to clean, low shear cover; Top cover is fluid resistant; Bottom cover is waterproof Convoluted high-density polyurethane foam topper; Split bladders contain an aqueous non-toxic gel solution and prevents migration Overall Dimensions: 78"(L) x 34"(W) x 4"(H); Weight Capacity: 650 lbs