Now you can glide smoothly across carpets, sidewalks and doorways with these specially designed walker coasters. Replace those unsightly tennis balls or dangerous wheels on your walker and easily add these smooth, durable rings that work well on a variety of surfaces. The set of 2 coasters give you the stability you need, with safer, smoother gliding action. The grey coasters fit easily on standard 1" walker tubing and can be used indoors or outside. Plastic. Each is 1 1/2"H x 2 1/2"Dia.