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. Also available in sacro versions with a coccyx (tailbone) cut-out to reduce spinal pressure. Made of high quality polyurethane foam and covered with a washable, durable twill fabric. Also available in the Viscoelastic memory foam version with removable/replaceable coccyx cutout.