A layer of capsulated gel that is 2mm thick. 15 degrees cooler to the touch and stays cooler up to 6 times longer! * Breathable fabric to allow maximum effectiveness of cooling properties. * Stretch-to-fit skirt to prevent sliding or movement of gel layer and for perfect fit up to 20" mattress. * A 360 degree zipper that allows top cover to be removed and then machine washed for easy care. * Twin - 39" x 75" x 17" (gel sheet 39" x 55")