8-Piece Shower Door Roller Set: Includes 4 upper rollers and 4 lower rollers, 8 in total; Comes with screws and a plastic cover. Suitable for glass shower doors, shower enclosure doors, massage cabin doors, or sliding furniture fittings. Shower Enclosure Roller Material: Made of brass and ABS plastic, sturdy and durable. Size: The wheel size is approx. 23 mm in diameter, 6 mm in width; the maximum glass thickness is 6 mm; the distance from the center of the mounting hole to the edge of the glass is approx. Easy to Slide: The bathroom glider is easy to move and install, keeps the door balanced, and allows the door to slide with minimal effort.