MATERIALS: Sliding gate wheels are made of high quality galvanized steel, sturdy, durable, corrosion resistant and waterproof for long time use SIZE: Groove wheel diameter is 50mm, wheel inner width is 20mm, outer width is 30mm, groove depth is 8.95mm. Fits 90 degree v-track (please confirm v-track size before ordering) LOAD CAPACITY: The thickness of the carrier is 3 mm, which allows a capacity of 300 kg per wheel for an easy to transport door ROLLER CARRIAGE: The double roller bearings glide steadily and smoothly, making pushing the door effortless PERFECT FOR: Heavy duty sliding door, factory door, dog door, garage door, garden door, driveway door, reverse lane, industrial machine track project Size:4 Pcs Our v-groove steel wheels are made of high quality galvanized steel, which is sturdy, durable, corrosion resistant and waterproof. It's easy transport heavy objects and the load capacity is 300 kg per wheel. It is perfect for sliding doors, factory doors, dog doors, garage doors, garden doors, driveway doors, reverse lanes, building projects< /p> Industrial machinery tracks. Specifications: Material: Galvanized steel Cargo capacity: 300kg per castor Wheel diameter: 50mm Wheel inside width: 20mm Wheel outer width: 30mm Groove depth: 8.95mm Groove width: 3mm Frames Size: 68 x 38mm (L x W) Stand thickness: 3mm Bolt hole distance: 55 x 24mm (L x W) Package content: 4×V-groove castors Scope of delivery: 4 pieces lucky meet Note: The data is manual measurement, please allow 1-21cm error, due to the light and screen differences , there will be a certain color difference, the specific received in kind prevail.