Package Content: Set of 4 twin shower door rollers (2 top and 2 bottom). Galvanized door rollers: 23mm diameter, plated surface, rust-resistant; suitable for glass door thickness of 4-6mm and glass hole diameter of 13.5-14mm. These replacement shower door wheels are compatible with most shower enclosures, shower cubicles, and steam cabins, installed at the top and bottom of the shower door for smooth and easy operation. Quiet operation when opening and closing the shower door; the rollers ensure smooth sliding. Easy to install and maintain. The shower door sliding casters are made of electroplated plastic alloy, resistant to rust. The material helps reduce the risk of glass breakage from impact while maintaining strength. Copper swivel and stainless steel screws enhance durability. Includes 4 anti-collision blocks to help protect your shower door. Adjustable height via screw for proper glass alignment. Bottom roller height is adjusted in relation to the top roller. Designed for glass holes of 13.5-14mm. Due to manufacturing tolerances, there may be a 0.5-1mm variation. Most shower door rollers accommodate this range. If uncertain, measure the glass hole diameter manually. Ideal for sliding glass doors, including bathroom and patio doors. Compatible with most shower rooms and steam rooms. Note: Due to manual measurement, please allow a 0-2cm size difference. Color may vary slightly due to monitor calibration differences. Delivery quantity: 4 pieces