The Kolbs Gel Extreme is a pressure-reducing wheelchair cushion designed to assist in the prevention and relief of pressure-sore ulcers. A thick fluid gel core is sealed in a leak-proof bladder providing excellent pressure distribution. This specially designed gel bladder is encased in medical grade high density foam offering the utmost in comfort. Not just for wheelchair users, this cushion is ideal for all chairs. Choose the size that fits your chair. * EXTRA THICK PRESSURE RELIEVING GEL: Trusted by medical professional for managing pressure ulcers and sores. * 5 LAYERS FOR ULTIMATE COMFORT: 1. Water resistant top cover. 2. High density foam for support.