MATERIAL: Made of high quality galvanized steel, sturdy, durable, water proof and anti-corrosion SIZE: Wheel diameter is 50mm, interior width of the wheel is 22mm, exterior width is 30mm. Fit the 19mm round tube orbit (Please confirm your size of tube orbit before order) LOAD CAPACITY: With 3mm thick bracket, each u groove gate wheel loads up to 270kg, easy to carry up heavy duty gate Roll Bearing: Double roll bearings make sliding stable and smooth, easy to push the gate GREAT FOR: Inverted track, industrial machine, rolling gate, sliding door, factory gate, drive way door, dog gate, container shelf Product description These U groove gate wheels are made of high quality steel with galvanized, which is strong, durable, water proof and anti-corrosion. It is perfect for inverted Track, industrial machine, rolling gate, sliding door, factory gate, drive way door, dog gate, container shelf. Specifications: Material: Galvanized steel Wheel Diameter: 50mm Interior Width of Wheel: 30mm Exterior Width of Wheel: 22mm Bracket Size: 68 x 38mm (L x W) Bolt Hole Distance: 47 x 18mm (L x W) Bracket Thickness: 3mm Loading Capacity: 270kg Colour:As Shown Package Includes: 4 U-Groove Gate Wheels