4" diameter discs move everything as if it had wheels. Move up to 3200 lb. Won't scratch your floors. Works on any kind of surface: Wood floors, vinyl, ceramic tile, and carpeting. Move any heavy furniture or appliance and then remove and reuse. Will slide over doorsteps or floor edges with a height difference of up to 3/16". Color: Grey. Contents: 4 reusable sliding discs. As seen on TV.