Features:V-shaped wheel can perfectly adapt to the inverted track, and might lower vibration, appropriate for V-shaped groove trackSpecification:Material: SteelBase plate diameter:1.2 Inch-- 56mm*30mmA unmarried load-bearing capacity:1.2 inch--200kg (440 pounds)Package Contents:4pc Wheel Note:1. The genuine color of the object may be slightly varied from the pictures shown on web page brought on by many points corresponding to brightness of your computer screen and lightweight brightness.2. Please enable slight handbook size deviation for the data.