Togu T400340 DYNAIR Premium Seat Wedge Represents a perfect combination of the advantages of the classic sitting cushions: the wedge cushion and the air-filled ball cushion Angled to promote proper posture and provide maximum comfort and support, supports an upright posture, strengthens the back muscles and helps to relieve back pain The firmness can be customized to the user's preference, utilizing the needle valve and pump, small hand pump included The wedge has two surfaces: one being smooth for normal sitting and the other having senso knobs ideal for foot and back massage The seat wedge is air-inflatable and constructed of durable PVC, recommended for adults