Package Contents: Set of 4 double shower door rollers (2 pcs on top and 2 pcs on bottom). (recommended for 14mm glass hole) Galvanized Door Rollers: Double top and bottom shower door rollers. 23mm (diameter) bottom, plated surface, anti-rust; Suitable for glass door thickness of 4-6mm, open glass hole of 13.5-14mm. These shower door replacement rollers fit most shower enclosures, shower stalls and steam rooms and attach to the top and bottom of the shower door for easy opening and closing. (recommended for 14mm pinhole glass). No noise when opening the shower door These glass shower door rollers ensure smooth sliding. It's easy to install and maintain. (recommended for 14mm glass holes)