A positioning cushion for those who slide forward in their chair. These polyurethane foam wedges are 4.5 in (11 cm) high at the front, tapered to 3/4 in (1.9 cm) at the back. All come with tie straps at the back to hold them in place. This hard based version corrects sagging sling seats in wheelchairs. Cushion measures 16 in (40.6 cm) in depth (from back to front) and 18 in (45.7 cm) in width.