In metal and plastic, with wheels. It slides easily and is very strong. Suitable for cupboards, cupboards, bookcases and other office furniture. Note: the diameter of each wheel is 14.5 mm. Before buying, please make sure it matches the size of your furniture Features: Made of metal and plastic, with wheels. It slides easily and is very strong. Suitable for cupboards, cupboards, bookcases and other office furniture. Note: the diameter of each wheel is 14.5 mm. Before buying, please make sure it matches the size of your furniture. Details: Material: metal and plastic. Color: Silver / White Dimensions: Central thickness: 5.5mm Outer width: 17.5mm Suitable for track height: 15-20MM Curb soft channel inner width: 18-23MM Track center width: 6 to 7.9MM Wheel diameter: 14.5mm. Package content: A set of 10 wheels.