I was checking out a website for quality replacement barrels for my Glock 23 and ran across threaded barrels and compensators and other accessories to screw onto a threaded barrel. Then I found a FLASH SUPPRESSOR! I have never seen a flash suppressor for a pistol. What is the purpose? Is it intended to reduce muzzle-flash when firing in low-light conditions so as not to ruin one's night-vision? I'm confused.