Hi-Tech physiotherapy design is adopted to correct the sitting posture of the back and relax the waist when you sit for a long time. With in line High/ Low/Off switch, the vibration can be adjusted according to your needs. The design is reasonable with the massage function and contributes to blood circulation of the body. This Back Seat Massage Pad is suitable for 12v Dc. It features soft sponge stuffing with removable fabric cover. You can also use this for your home or office(Ac to Dc converter is not sold with this package). Back of the cushion has an elastic strap to hold it in its preferred position. Dimension~13.5 x 12.5 x 4"(L*W*H). Items Included 1 x Relaxing Back Seat Massage Pad Beige.