Made of iron, sturdy, durable, high strength, good stability, low creep. Good wear resistance and chemical stability, can be used for a long time. Double bearings together with its structure ensure stability and smoothness when the door is rolling. Reduces vibration, reduces noise, and ensures smooth operation. Ideal for internal or external use. Widely used as spare parts, door wheels, sliding fence components, sliding window bearings, 3D printer parts, shower screen bearings, can washers, dog doors, gates, fences, wire rope guides, etc. Suitable for professional (industrial context) or DIY applications. Easy to install and use for both experienced and non-expert users. Wheel diameter is 15mm, wheel overall height is 28mm, U-groove depth is 4mm. The U-shaped groove fits the inverted track perfectly. Maximum load capacity: 40kg. Iron as main material; do not use in humid environments.