new style hex auto bolts and nuts

 the rear hold cap is the most important key to play a locking effect , it has a fastening outside cone consistent with the taper of compression cap ,the diameter of cone is greater than the one which in the compression cap .When installing it , the cone outside will express inward along the cone within the compression cap ,under the express of the inside cone ,the pore size of outside cone will narrow ,when the hexagonal part of the two themes all  pressed ,the outside cone of lock nuts has already hold fast to the fastening bolts.