The Drive Back Cushion with Lumbar Support improves seating posture while providing back and lumbar support, for a more comfortable wheelchair experience. A sealed liner protects the foam core from moisture, ensuring a durable, long lasting product. The stabilization board secured on the back of the foam core prevents hammocking in sling-back wheelchairs. This wheelchair cushion has a non-slip vinyl back to prevent it from sliding around. Choose from two sizes, 16" x 17" or 18" x 17".