[ wheels] - These wheels are mainly used for luggage, training wheels or children's indoor roller skating. It is not recommended to use on uneven ground. [Sturdy material] - These rollers are made of high-quality PU, wear- and sturdy. Designed with 85A hardness, it provides a long-lasting experience. Its high-performance bearings stability and comfort. If the buckle inside the wheel core is loose, it is recommended to add a little paper between the white plastic lip and the bearing to better fix the wheel. [Practical and convenient] - High-tech elastic material makes it easy to move. Perfect for indoor daily practice, leisure skating, very convenient and practical, allowing you to enjoy skating time. Colour: Black Silver Material: PU Size: 80mm Package Contents: 1 x 85A high elastic PU wheel Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.