There is no noise when opening the shower door, and these glass door rollers help it slide smoothly. It is easy to install and maintain. (Suggested 14mm glass hole, not suitable for glass holes below 12mm) Package includes: a set of 4 double shower door rollers (2 at the top and 2 at the bottom). (Suggested 14mm glass hole, not suitable for glass holes below 12mm) These replaceable shower door rollers are suitable for most shower rooms, shower rooms, and steam room casings, installed at the top and bottom of the shower door, making it easy to open and close. (Suggested 14mm glass hole, not suitable for glass holesbelow 12mm) Electroplated door roller: 23mm (diameter) wheel top and bottom shower door roller, electroplated surface, rust proof; Suitable for glass doors with a thickness of 4-6 mm and glass openings of 12-14 mm. (Suggested 14mm glass hole, not suitable for glassholes below 12mm) Thank you for purchasing our glass door hinges. Please check the size before purchasing.