Material: ABS + zinc alloy. Supplied with screw cover. Easy to slide and clean. Dimensions: suitable glass thickness: 6-8 mm, diameter of the wheel: 26 mm, diameter of the hole in the glass: 10-14 mm. Screw caps: the truck is held in place with a screw and this is covered with a chrome plastic cover which makes it pleasant to the eye and easy to clean. Field of application: suitable for sliding shower doors flat and sliding shower doors. Set of 4 upper shower door rollers and 2 shower door rollers. " Features: Color: As the picture shows. Material: ABS+Alloy of zinc. suitable glass thickness: 6-8 mm. Diameter of the hole in the glass: 10 mm -14mm. Wheel diameter: 26mm. The center of the glass hole to the bottom of the glass: 15-17mm. Contents: 2 upper pulleys. 2 lower pulleys. 4 protection blocks. 4 screws.