This is a metal adapter that allows you to attach tires to the zp1007 using M4 nuts. The genuine product is made of plastic, so there are concerns about its strength and durability. Also, the genuine product uses a screw-in mounting method, so there is a concern that the tires may come off while driving. By replacing it with this product, you can change to mounting with M4 nuts, which is used by most hobby RC cars, so the mounting strength will be greatly improved. This product is my original product, so it is not sold anywhere else.