The BetterBack Deluxe is an ergonomic lumbar support accessory for dexterity. The accessory works by providing stability to your pelvis when you sit and allowing your spine to rest in its neutral and upright position. The BetterBack support accessory uses an adjustable knee straps to position the product. The back pad is made of NASA memory foam and its lightweight makes for easy adjustments and for use with most chairs. Supports up to 36” waist.