The Drive Medical Tennis Ball Glides are unique in appearance and in use. Unlike normal tennis ball glides, these feature a removable and replace tip - which is really the only part of the ball that makes contact with the ground! These tennis ball glides provide a quiet, smooth, and durable glide experience when used with a walker. Each glide tip has a lifespan of approximately one year - longer than that of regular plastic glide caps. This product includes a pair of replacement glide pads, but you can also purchase more here.