Features: -Made of high-quality galvanized steel and TPR material, it has a sturdy structure and can perfectly support 100kg gate or fence. -Thanks to the ball bearings, you can easily adjust the direction of movement. -The built-in spring, which extends up to 44 mm, helps ensure that the door is well supported and the load on the door is well balanced. -Easy to install, with 3 screw holes, just tighten the screws. -Suitable for all kinds of ground, the wheels can move evenly even on uneven floors (please note that it cannot be used on deep pits or very uneven ground). Specification: Colour: silver,black Material: galvanized steel+TPR Wheel Size: 4 inches .