The Vortex flash hider uses a patented 15 degree, right hand helical flute design to eliminate muzzle flash. Used by US armed forces worldwide as well as US Dept of Homeland Security and law enforcement across the nation. Machined from ordnance grade 8620 steel and finished with a mil-spec phosphate. Designed not to loosen under sustained fire. Compatible with Smith Enterprise's quick attach/detach Direct Connect (DC) sound suppressors. This model is designed for use with AR-15 variants in calibers other than 223/ 5.56mm, up to 30 caliber.