1. Material: The caster is made of highquality carbon steel TPE rubber material, featuring a colorful galvanized surface with rich color and smooth finish, rustproof, sturdy and durable. Features: Builtin precision single ball bearing, integrally molded, 360° rotation, stable operation. Cover design prevents tangling and dust. TPE material tires are quiet and smooth, protecting floors from damage. Bracket Features: High mechanical strength, wear resistance, and shock absorption. The expansion tube design enhances stability and load capacity. 2. Features: Builtin precision single ball bearing, integrally molded, 360° rotation, stable operation. Cover design prevents tangling and dust. TPE material tires are quiet and smooth, protecting floors from damage. 3. Bracket Features: High mechanical strength, wear resistance, and shock absorption. The expansion tube design makes the wheel more stable and loadbearing. Includes 4 heavyduty swivel casters with M12 x 60 mm threaded rods and expansion tube size of 22 x 50 mm. 4. Installation Method: The wheel has a round valve stem (suitable for 22 to 24 mm round tubes). Simply insert the wheel stem into the hole and tighten it securely. (Please confirm the size before purchasing.)