Material: Made of POM, it combines high stiffness and strength with excellent elasticity, good sliding friction properties and excellent dimensional stability in fuels and other fluids and at high temperatures. Brass shower door rollers, screws are made of stainless steel, corrosion resistant, rustless, durable and long service life. Dimensions: Roller Diameter: 19mm/0.78 inches; bore: 5mm/0.19in; wheel thickness: 5.5mm/0.21inch; screw length: 12mm/0.47inch. Rolling parts: smooth door operation, slight forward or backward movement, easy shower rollers for shower stalls shower, the hydromassage box clearly performs its assigned task, assigns the mass of the glass, controls the movement in a given direction . This makes the product more durable and lasts longer. Waterproof: When the shower enclosure uses a special ultra-waterproof grease with Teflon, the wheels will last much longer. It 100% prevents problems, protects the product from corrosion, creates a durable waterproof protective layer and helps extend the life of the mechanism.