DONUT DESIGN CUSHION: Sleepsia tailbone support Cushion, which is shaped like a donut and has an ergonomic "U" shaped cutout, provides natural support for your most sensitive areas while conforming to the contours of your lower body. IDEAL SEAT CUSHION FOR RELIEF OF TAILBONE PAIN: The Donut seat cushion provides adequate support to the lower back, thighs, and buttocks. Sleepsia donut shaped tailbone support which comes in high-quality & durable materials, that are breatheable to prevent sweating. PERFECT FOR MOST SEATS: This Orthopedic Seat Cushion for sitting fits most office chair, car seat, dining chair, gaming chairs, wheel chair & on the floor. EVEN WEIGHT DISTRIBUTION: The Ring-U shaped form of the pillow distributes pressure evenly while you sit, which relieves a lot of pressure on your tailbone and coccyx. The non-skid backing on the pillow's back keeps it from slipping. DIMENSION: 17.5L X 14W X 4H (Inches)