Feature:The correct posture is related to the health of the back. The front M shape of this Coccyx Seat Cushion is designed to fit the curve of the thigh and support the legs. The hollow design in the rear is good to protect the coccyx. The inner is space memory foam which can recover to its original shape after the pressure left. The cover breathable knitted fabric which is made of 82% cotton. It is durable and does not pilling easily.The outer cover can be made in many colors, such as black, red, purple,blue,pink and so on.