Multiple inserts are available to make your Wolverine one of the most versatile silencers you own. The smaller threads will use the M14 Collar, M24 thread will use the M24 collar, and the M26 thread will use the M26 collar. Note: Bulgarian Krinkov/SBRs take the 24mm LONG Insert *Special note Polish WZ88 "Tantal" rifles have a unique barrel/thread profile that we do not accommodate currently. The muzzle extends well past the threads and that does not work with our system. They cannot be cut to thread length without being an SBR. It's an issue we may address at some point, but for now, the Wolverine cannot mount to them.