4pcs 23mm Double Top and Bottom Shower Door Rollers/Runners/Wheel Hubs Zinc Alloy + Stainless Steel Home Showers Door Slid WheelsDescription: These rollers fit for glass where the distance between the center of the fixing hole and the edge of the glass is 18mm. The minimum hole size is 6mm. The truck is held in place with a screw and is covered with a chrome-plated plastic casing, making them pleasing to the eye and easy to clean. The maximum thickness of the glass should be 6mm. Rotary action to also fit curved and quadrant showers. They are spring-loaded to allow the door to be positioned to connect to the frame or magnetic seal where you have a pair of doors. Suitable for most shower enclosures, shower enclosures and steam enclosuresEasy glide interchangeable shower enclosureMaterial: zinc alloy, stainless steelColor: silverWheel diameter: 23mmWheel width: 6mmPackage included:2 pcs. Lower roller + 2 pcs. Top RollNote: 1. Please allow 0.1-0.3cm differences due to manual measurement, thanks.2. Please understand due to the light exposure or the monitor to the computer difference, so I can't guarantee that the pictures and the actual colors are the same.