These muzzle devices are HK patterned (to 9mm specs) and will interface with any standard 3-Lug mount. The 5/8x24 version requires an extension to reach the proper diameter and is the larger device pictured. All other mounts are the smaller sized mounts. The 5/8 mount is also bored for use with .300blk and will not run on a 9mm platform. On a completely scientific side note: The m13.5x1LH will turn your MPX into a slick little QD system if you also have a Griffin Optimus or Revolution.
