High quality: high quality POM plastic. Adapts to different types of showers. Guarantees your doors a more comfortable glide No decompression and no waste of money: have you bought a sliding system and it is broken You think with horror that you now have to buy a new one. Forget! There are replacement shower door rollers that will fit any sliding system in your home. If you are having difficulty sliding shower doors, use this quick fix and don't waste your money Use anywhere: shower door sliders for showers, massage cabins, bathtubs, jacuzzis and even for furniture accessories. Make sure the door(s) open easily and smoothly. Replace your broken system. Premium Shower Rollers Rolling Component: Smooth rolling of the door with a slight forward or backward movement effortlessly for shower enclosures, Hydromassage Doors clearly performs their assigned task, distributes the mass of the glass, controls the movement in the given direction. This gives the product even more durability and a longer life Steel part of the wheel: 9 mm diameter x 3 mm height Type: 4 shower door rollers. wheel thickness: 5 mm. Delivered with screws. Suitable for 4-6mm thick shower door. Roller diameter: 20mm, inner hole 6mm, fixed with M6 screw. The pulley is made of copper + POM wheel, and the screw is made of stainless steel. Corrosion and rust resistant steel, good all-round performance. Pulley bearing capacity, good stability, small friction coefficient, good mute effect. Easy installation, often used for bathroom sliding glass door pulley.