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 only 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: Roller diameter: 20 mm / 0.78 in; inner hole: 5mm/0.19in; wheel thickness: 5.5mm/0.21in; Screw length: 12mm/0.47 in. Rolling Component: Smooth door operation, slight forward or backward movement, effortless shower rollers for shower enclosures, hydromassage casings clearly perform their assigned task, distribute the mass of the glass, control the movement in the given direction. This gives the product even more durability and a longer life. Waterproof: When using a special ultra-waterproof grease with PTFE content for shower enclosures, the service life of the wheels is much longer. It certainly works 100% to prevent problems, protects the corrosion products, creates a long-term water-repellent protective layer and helps the mechanisms to extend the service 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. Product Material: The pulley is copper+POM wheel and the screw is stainless steel. Size: Roll diameter: 20 mm/0.78 in; inner hole: 5mm/0.19in; wheel thickness: 5.5 mm / 0.21 in; screw length: 12 mm/0.47 in. Quantity: 4 pieces Application: Suitable for most shower enclosures, shower enclosures and steam cabins Notes: 1. Due to the light and screen difference, the product color may be slightly different from the picture. 2. Please allow 0.5-2cm differs due to manual measurement.