This donut cushion is made of high-density rebound memory foam which provides strong support and makes it impossible to go flat with long-term use. The unique donut design helps to properly distribute the weight of the sitting body, helping to promote healthy blood circulation and posture as well as spinal alignment. Silica gel particles make up the non-slip bottom which keeps the cushion in place. Cushion has a soft handle which makes it easy to carry. Removable cover is machine washable.