Sliding Door Roller, 4 Pcs Shower Rollers, Shower Runners, Roller Caster Wheel For Shower Door Sliding Rollers Door(20mm) 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: Roller diameter: 20mm/ 0.78in; 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, shower enclosures hydromassage clearly perform the task assigned to them, distribute the mass of the glass, control the movement in the given direction. This gives the product even more durability and a longer service life. Waterproof: When using a special ultra-waterproof grease with PTFE content for shower enclosures, the wheel life 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 their life. Uses: Door rollers rollers are what makes it easy to open the shower door, rollers for massage cabins in showers, bathtubs, whirlpool tubs and even for furniture fittings.