This Banish Tri-lug adapter is required for up to 9mm Firearms threaded in 1/2x28. Pistol-caliber carbines are growing in popularity and for those with a three-lug mount, these adapters will allow you to mount your BANISH 45 suppressor. This Tri-lug adapter is required for up to 9mm Firearms threaded in 1/2x28 when mounting a BANISH 45. It is the necessary adapter that attaches to firearm and mates with Banish Tri-Lug Housing Assembly for mounting the BANISH 45 suppressor. It gives you quick attach mounting options for fixed barreled carbine firearms. Note: Must be used with the BANISH Tri-lug Housing Assembly (sold separately).