Material: It is made of POM which combines high stiffness and strength with exceptional resilience, favorable sliding friction behavior and excellent dimensional stability, fuels and other fluids as well as at high temperatures. Brass shower door roller, and the screws are made of stainless steel, corrosion resistant, non-rusting, durable and have a long service life. Dimension: Roll diameter: 20mm/0.78in; inner hole: 5mm/0.19in; wheel thickness: 5.5mm/0.21in; Screw length: 12mm/0.47 in. Bearing Component: Smooth operation of the door, slight forward or backward movement, effortless shower rollers for shower cabins, hydromassage boxes clearly perform their assigned task, distribute the mass of glass, control movement in the given direction. This gives the product even more durability and a longer lifespan. Waterproof: When using a special ultra-sealing grease with PTFE content for shower enclosures, the service life of the wheels is much longer. It certainly works 100% to prevent problems, protects products from corrosion, creates a long-lasting water-repellent protective layer and helps mechanisms extend life. Uses: Shower door rollers are what makes it easy to open the shower door, rollers for massage shower stalls, tubs, hot tubs and even for furniture trim. Color as shown Quantity delivered: 4 pieces