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. Smith Enterprise's newest offering is the upgraded G6A4 Vortex with Arc Helix. The Arc Helix has been designed to even further facilitate the installation/removal of the SEI Windtalker sound suppressor, coupled with a shallower pitch and grooves to reduce surface contact and carbon buildup. Through test and evaluation Smith Enterprise has also found that the Arc Helix has proven itself to retain better accuracy as the round leaves the suppressor. Due to the design of the Vortex flash hider, no crush washer is needed to install this sight and it is not recommended that one is used.