Wondergel DoubleGel Seat Cushion for Home, Office or Auto 2" Of Ultra-Plush Supportive WonderGel Deluxe, Washable Cover (Black) w/ Carrying Handle. Soft Side and Firm Side for Your Choice of Comfort. Extra Pressure Relief for Longer Sitting. WonderGel is the most advanced cushioning material available today. Measures: Full 15.5" x 17.5"