Specifications: 1.Roller diameter 27mm. Suitable for arc or square old-style shower room. 2.Attention: 4-6mm door thickness, installation aperture 15-17mm. 3.Material :Copper+stainless steel+nylon. Features: 1.Strong Load-bearing capacityBold copper shaft is more load-bearing. 2.Ultra-quietBuilt-in smooth ball, sliding silent, smooth and powerful. 3.Smooth:The upper rail is evenly stressed, stable and smoothly pushed and pulled; the lower rail slides smoothly, labor-saving and safe to use. Installation steps: 1.Take the glass door out of the track. 2.Unscrew the fixing screws and remove the old pulley. 3.Install the pulley on the glass door, fix it with screws, and then install the screw cover.