[DURABLE CONSTRUCTION]-- Made of Metal, easy to dissipate heat, and it can the flexible rotation that durable. [ MOTION]-- With , axle and extra side plug to fix the bearings better, which is helpful to reduce drag on your bearings and make the motion of more smoothly, helping to prevent your bearings from collapsing. [EASY TO MATCH]-- The recessed part of the fits between the bearings, providing a seamless integration to the wheels, which makes it easy to support the wheels and bearings, and they are easy to match the skating male and female axles. [COMPATIBILITY & SIZE]-- Axle diameter 6mm, inner diameter 6mm, wheel inner diameter 8mm, suitable for most roller skates model using 6mm axles. check the specifications in the second product to it match your specifications. It is important to measure your wheel dimension to a proper fit. Style:A Colour:silver :Metal Package Contents: 10 * Axle 2 * wrenches 16 * side plugs 8 * three-section aluminum casing 10 * Screws Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.