Seat wedges are designed to relieve and help prevent lower back pain. The tapered angle of the wedges encourage correct posture. Available in various sizes and sacro versions with coccyx (tailbone) cut-out to reduce spinal pressure. Made of high quality polyurethane foam and covered with a washable durable twill fabric. Cut-Out relieves pressure from Coccyx area. Supportive Polyurethane foam. Durable twill fabric.