MaterialThe shower door roller is made of zinc alloy and ABS material. It is sturdy and durable, stable in quality and has a long service life. Quantity: 1 set of 4 double shower door rollers (2 upper and 2 lower). A practical hardware for the sliding shower door. During the day and night, it can effectively reduce the noise that occurs when the door is closed. SizeWheel diameter: 25mm; the bath mat is suitable for glass doors with a thickness of about 4-6mm. ApplicationSuitable for most shower partitions, shower cabins and massage cabins. Suitable for 4-6mm thick glass. 1. The casters make no noise when walking on the rail, quiet and stable. 2. Easy and convenient to install, but we recommend professional installation. 3. Ideal for sliding glass doors, windows and bathroom doors.