Used by US armed forces worldwide, the US Dept of Homeland Security and law enforcement agencies across the nation, the Vortex flash hider features a patented 15 degree, right hand helical flute design that effectively eliminates muzzle flash. Machined from ordnance grade 8620 steel and finished with a mil-spec phosphate, the Vortex is a self-tightening flash suppressor that will not loosen or shift position under sustained fire. The new G6A3 Vortex comes equipped with a grooved exterior for less contact surface and reduced carbon build up, making the removal sound suppressors easier. Compatible with Gemtech HALO and Smith Enterprise/Fisher quick attach/detach Direct Connect (DC) silencers. Notes: Due to the design of the Vortex flash hider, no crush washer is needed for installation. It is not recommended that one is used.