MATERIALS: The sliding gate wheels are made of high quality galvanized steel, sturdy, durable, corrosion resistant and waterproof for long time use SIZE: The diameter of the groove wheel is of 50mm, the inner width of the wheel is 20mm, the outer width is 30mm, the groove depth is 8.95mm. Fits 90 degree V-track (Please confirm the V-track size before ordering) LOAD CAPACITY: The thickness of the bracket is 3mm, which allows a capacity of 300 kg per caster for an easy-to-transport door ROLLER CARRYING: The double roller bearings slide stably and smoothly, allowing the door to be pushed effortlessly PERFECT FOR: Heavy duty sliding door, factory door, dog door, garage door, garden door, driveway door, reverse track, industrial machine track project Size:4 Pcs Our steel wheels with V groove are made of high quality galvanized steel, which is sturdy, durable, corrosion resistant and waterproof. It is easy to transport heavy objects and the load capacity is 300 kg per caster. It is perfect for sliding doors, factory doors, dog doors, garage doors, garden doors, driveway doors, reverse tracks, projects of industrial machine tracks. Specifications: Material: Galvanized steel Loading capacity: 300kg per caster< /p> Wheel diameter: 50mm Wheel inner width: 20mm Wheel outer width: 30mm Wheel depth: groove: 8.95mm Groove width: 3mm Frames Size: 68 x 38mm (L x W) Bracket thickness: 3mm Bolt hole distance: 55 x 24mm (L x W) Package contents: 4V groove casters Quantity delivery: 4 pieces