Features Smooth Sliding: 4 wheel design ensures smooth rolling performance with good stability, and the operation is very safe and easy with low noise. Good Structure: Adopting rolling bearing, the trolley assembly has been through fine welding and CNC crafting to form highly sturdy structure. Extensive Uses: Allows for wide application on home movable doors, wardrobe, large iron doors, curtains, automatic equipment components, etc. Steel Material: The utilization of premium carbon steel and stainless steel materials enables greater durability against rusting and corrosion. Easy to Install: Comes with a compact size and a light weight as well, the trolley roller is very convenient to install within several minutes. Specification: Item Type: Trolley Assembly Material: Carbon steel, stainless steel. Color: Silver Use: It can be used for home movable doors, wardrobe, large iron doors, curtains, automatic equipment pulley components, and factory track pulley.  Package List: 1 x Trolley Assembly Package List 1 x Trolley Assembly