Solid Back Insert Wheelchair Cushion 18 x16 x1.25 w Strap Pillow Cases Protectors With Post Valve (need o2 Color:Red With Post Valve (need o2 wrench to turn on off) * E Tank 682 Liters * * Telescoping parts are manufactured with internal bushings and external lock nuts to provide totally silent usage SOLID SEAT BACK * 18 W x 16 D x 1 1 2 * Custom and bariatric sizes are available * Used to properly align the body as well as to eliminate the sagging effect found in standard sling seat wheelchair upholstery * Safety straps secure the solid back to the wheelchair * Cushion uses medium density foam and is covered using waterproof black leatherette cover