Kang Li Coccyx Orthopedic Extra Large Memory Foam Seat Cushion (Black) Features: Large size, soft and comfortable, The buttocks is fully protected  size: 20 inches  20 inches  3 inches at home or office, Superior comfort for a chair, car seat, plane or wheelchairUse it to relieve fatigue sedentary Assists in the relief and treatment of lower back pain, numbness, and pressure sores Patented design promotes healthy weight distribution, posture and spine alignment / Removable velour cover is machine washable and allows for easy cleaning Kang Li Product , the absolute high quality, please rest assured purchase 100% Customer Satisfaction or Money Back Guarantee; try for 30 days; if it doesn't relieve your pain, we'll give your money back