8PCS Up and down Single Wheel Nylon Bouncing Wheel Bathroom Glass Sliding Door Pulley Shower Room Accessories Specification:Pulley diameter: 23MMSet of 8 Pcs Single Shower Door Rollers (4 higher rollers and four bottom rollers) single bathe door rollers fit glass shower doorways the place the gap from the middle of the hole to fringe of glass is 18mm.Diameter of the wheel: 23mm; Width of the wheel: 6mm. Minimum Hole size within the glass: 11mm. Maximum glass thickness: 6mm.Material: Plastic, Nylon, A Plastic, Nylon BS and stainless steel.Comes with screw disguise caps. Spring loaded movement also can fit curved showers. Designed with a nut and a plastic cover. Package Includes:8PCS x Shower Door Rollers