What's Included: 4 Double Shower Door Rollers (2 at the top, 2 at the bottom). (recommended for 14mm glass holes, not suitable for glass holes under 13mm) Plated door roller: 23mm (diameter) roller top and bottom shower door roller, surface plating, anti-rust; suitable for glass doors with thickness of 4-6mm and glass openings of 13.5-14mm. (14mm glass hole is recommended, not suitable for glass holes below 13mm) These replacement shower door rollers fit most shower, shower and steam room enclosures and fit on the top and bottom of the shower door for easy opening and closing. (14mm glass hole recommended, not suitable for glass holes under 13mm) Opening the shower door makes no noise and these glass door rollers help it slide smoothly. Easy to install and maintain. (14mm glass hole is recommended, not suitable for glass hole below 13mm) Shower door double rollers are easy to install, please determine the size of the rollers you want and the diameter of the glass hole. (14mm glass hole is recommended, not suitable for glass hole below 13mm)