Package ContentsSet of 4 Twin Shower Door Rollers (2 pcs top and 2 pcs bottom) and 4 rubber anti-collision block and 4 screws. Installed at the top and bottom of the shower door, for replacement shower door rollers Sturdy and DurableThe Shower Door Roller/Shower Enclosure Roller is made of high quality zinc alloy and brass, nylon. It is durable, waterproof and rustproof. It will not be affected by the humid shower environment Silent Roller The shower door roller is made of nylon, which can be rotated along the central axis. Whether it is a normal bathroom door or a curved bathroom door, it can be pushed and pulled smoothly, and it is not easy to make noise Diameter CastersShower Door Wheel up and down 23mm (diameter), Shower Door Rollers suitable for glass door thickness 4-6mm, glass open hole 12-14mm Applicable SceneThese Shower Sliding Door Roller are suitable for most shower stalls, shower stalls and steam rooms, it is convenient to open and close the shower door