Set of 8 small multi-purpose casters. Suitable for most shower enclosures, shower doors, and steam cabins. Materials: plastic, nylon, stainless steel, POM ball screw, ABS, brass axle. Wheels approximately 20mm diameter x 5mm thick. Screw size: M4 x 12 mm. Package contents: 8 x 20mm shower door rollers. Replacement roller helps to open the shower glass door smoothly. Shower door rollers are made of brass and nylon pulley, which are sturdy, durable, wear-resistant, and resistant to rust for long-lasting performance. Nylon pulley ensures smooth operation and effectively reduces noise when closing the door. Single shower door rollers are easy to install and replace. Ideal for use as bathroom replacement parts, suitable for shower enclosures, glass doors, bathtubs, and toilet partitions.