Long life: The shower door roller is made of high quality brass shaft and ABS material, it is rust resistant, sturdy and durable, stable quality and long life. Package includes: 4 Top Shower Door Rollers + 4 Das Shower Door Rollers Diameter of the castors: 23 mm; Width: 6 mm. Minimum size of the hole in the glass: 11mm. Suitable for glass thicknesses of sliding doors from 3 to 6 mm. Easy to install: The bathroom slider is easy to move and install, it can also move the door to save your space, more beautiful. Note: When the distance from the center of the hole to the edge of the glass is 18mm, these single shower door rollers are suitable for glass shower doors. Specification: Material: ABS and Alloy Roulette Diameter: 23mm Compatible Glass Thickness: 5-6 mm Weight: 180g Features: 1.Easy to adjust the height and angle of the door. 2.These shower door rollers can be used in quadrants, curved showers or straight sliding doors. 3.The shower door roller is adjustable, easy to install and the shower door is smoother than before, don't shake or scream! 4.No need to fish in cabins and plumbers or buy new shower doors. 5.Kit includes 4 upper adjustable shower door rollers and 4 lower shower door rollers. Note: Please check the size of the shower door glass hole before purchase. Package: 4x shower door rollers on top 4x shower door rollers at the bottom