The surfaces of both the acetabulum and the femur head are covered by cartilage to ensure smoother fit as well as allow for optimum range of motion. (mypetneedsthat.com)
They are so comfortable and very smooth fitting. (metrostyle.com)
It's made from cotton which is mercerised for a silky feel, and detailed with adjustable straps and seamless edges for a completely smooth fit. (polyvore.com)