Specifications: Wheel diameter: 19mm,23mm,25mm,27mm,29mm Materials: Plastic, Nylon, 304 stainless steel micro-bearing POM ABS brass axis Hole size in the glass: 15-17 Color: White Quantity:4pcs Package Contents: 4*Shower door rollers(other accessories are not included!) Note: 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. 2. Please allow slight manual measurement deviation for the data. *Made of high quality material, durable and practical to use *Suitable for most shower enclosures, shower cabins and steam cabin enclosures *Designed for use on 4-8mm glass doors *Easy glide rollers and easy clean *Quick Release Type