MATERIALS: The rolling gate wheel is made of high quality PU anti-corrosion steel, sturdy and durable, it has the characteristics of anti-oil, anti-corrosion and anti-rust DIMENSION: The total mounting height is 25.5cm wheel diameter is 5cm mounting plate is 7.5×4.5cm (L×W) LOAD CAPACITY: The maximum load capacity of each caster is 50 kg SPRING-DRIVEN DESIGN: the retractable gate wheel allows 6 cm of vertical movement, automatically adjusting the height on uneven ground to prevent it sagging, while ensuring the gate stays in contact with the ground as you open and close it easily and smoothly EASY TO INSTALL: Comes with 4 bolts, heavy duty universal mounting plate with 4 holes fits wooden garden gate, driveway gate and yard fence Note: The data is all measured manually, please allow 1-3cm error, due to the light and display difference, there will be some color difference, the actual object received shall prevail. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.