Plan B muzzle devices feature a taper followed by threads, resulting in repeatable lockup and a proper seal between the muzzle device and suppressor adapter. These Plan B muzzle devices are compatible with Plan B suppressor hubs. It is recommended to use Rocksett for installation and 20-25 ft-lbs of torque. Some suppressor manufacturers will not honor warranty claims if other brands of muzzle devices are used with their suppressors.Features :,Overall Length- 2.55";"Protrusion into Blast Chamber- 1.55""Weight- 3.7 oz17-4 StainlessBore- 5.56 and 7.62x39Installation Multi Wrench Included