This product includes :Wheel Hex 2pcsWheel Lock 2pcsM4x2.5x15 Screw Pin 2pcsProduct major functions & usage:1. Connecting the CVD to the wheels in order to transfer the power and lead a smooth drive.2. Lock and stabilize the wheel tightly.Major advantages of upgrading to this part/product:1. Made with a light material high tensile strength aluminum 6061 T6 for great sturdiness.2. Original thickness is 4.5mm, this part is upgraded to 10.5mm for wider wheel track in order to run smoothly and more stable.3. The hex are designed to claw onto the wheels tightly and firmly.4. Unique capped design to prevent sand and dust during the drive.5. Special knurling process on the inner part for tight locking.