Standard: These mounts contain a small tab inside the mounting hole to temporarily engage the threads, which allows assemblers to preinstall the mount on a stud before securing with a washer and a nut. For use with HellermannTyton heavy duty T120, T250, T255 and Wide Strap Cable TiesMedium: The arched H-profile of the saddle surface allows for a broad surface contact with the bundle, minimizing pinching and crushing of the bundles, and adjusts to a wide variety of bundle diameters when used with HellermannTyton heavy duty T120, T250, T255 and Wide Strap Cable Ties.High: The high-torque mount is designed for use with power-assisted impact wrenches and is molded with a heavy bushing to withstand the forces required to tighten grade 8 bolts. The arched H-profile of the saddle surface allows for a broad surface contact with the bundle, minimizing pinching and crushing of the bundles, and adjusts to a wide variety of bundle diameters when used with HellermannTyton heavy duty T120, T250, T255 and Wide Strap Cable Ties.