MATERIALS: Sliding gate wheels are made of high quality galvanized steel, sturdy, durable, corrosion resistant and waterproof for long time use SIZE: The groove wheel diameter is 50mm, the wheel inner width is 20mm, the outer width is 30mm, the groove depth is 8.95mm. Fits 90 degree V-track (Please confirm V-track size before ordering) LOAD CAPACITY: The thickness of the support is 3 mm, 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, making pushing the door effortless 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, backyard projects. /p> industrial machine tracks. Specifications: Material: Galvanized steel Loading capacity: 300kg per caster Wheel diameter: 50mm Wheel inner width: 20mm Wheel outer width: 30mm Groove depth: 8.95mm Groove width: 3mm Frames Size: 68 x 38mm (L x W) Media thickness: 3mm Bolt hole distance: 55 x 24mm (L x W) Package contents: 4V-groove casters Delivery quantity: 4 pieces