Package Content: Set of 4 twin shower door rollers (2pcs top and 2pcs bottom).(recommended for 14mm glass hole) Galvanized Door Rollers: 23mm (diameter) top and bottom double shower door rollers, surface plated, rustproof; Suitable for glass door thickness 4-6mm, glass open hole 13.5-14mm. These Replacement Shower Door Wheels are suitable for most shower enclosures, shower stalls and steam rooms, installed at the top and bottom of the shower door, for easy opening and closing.( recommended for 14mm glass hole) No noise to open the shower door and these glass shower door rollers help it slide smoothly. It is easy to install and maintain.(recommended for 14mm glass hole) Suitable material Our Shower Door Sliding Rollers adopts electroplating plastic alloy which is not worried about rust, on the other side, while ensuring the strength of the shower door roller slides, the plastic alloy significantly reduces the risk of glass breakage due to collisions. Copper swing and stainless steel screws should make the product more durable. Rollers up These shower door wheels fit 4-6mm glass thickness and 13.5-14mm glass opening, 23mm wheels diameter, there are 4 anti-blocking blocks additional collision protection to best protect your shower door. Adjust the height of the glass by screw. Rollers down The height of the bottom wheel is adjusted according to the top wheel.