The TBRC Glock Micro Comp is threaded in the standard 1/2×28 thread pitch. Therefore, It will work on most 9mm Glock barrels threaded in that pitch, including most 40-9 conversion barrels! The Micro Comp only adds about .50″ to the end of your threaded barrel (this will vary based on the spec of your barrel). This comp was designed for the Glock 19 and when installed will fit in all Glock 34/35 holsters. Although the comp was designed around the Glock 19, it will work very well with any 9mm Glock and will function with any open ended holsters in the event the gun is longer than the holster. Comp mitigates recoil and keeps your gun flat throughout recoil.