The OCS Ex Cel™ Positioning Wheelchair Cushion uses a nonliquid, nonmigrating gel to reduce body interface pressures at critical points. The contoured surface provides medial and lateral thigh positioning and pelvic positioning. All materials are bacteria resistant and the cover is fluid-proof.  The cushion straps securely to the wheelchair for consistent positioning and safe usage. An 18 month manufacturer's warranty also protects you against defective materials and workmanship. This cushion is 16 inches (40.6 cm) deep and 3 inches (7.6 cm) high and is available in three widths: 16, 18, and 20 inches (40.6, 45.7, 50.8 cm). Please specify Width when ordering.