The extra-large castors are made of rubber so that the floor is not scratched and the carpet remains intact. There is also no need for chair pads. The wheels roll quietly and do not slip, so you can comfortably control the direction and intensity of movement as you move. Replacing the wheels gives your chair a new lease of life. The set comes with 5 castors to fit the entire base of your office chair, gaming chair, swivel chair or children's chair. The set fits most office chairs on the market with a pin diameter of 11 mm. Push-and-click assembly is quick and easy: simply slide the pin into the recesses provided.