Knights Armament KAC Triple Tap Muzzle
The KAC "TripleKnight's Armament - Triple Tap Muzzle Brake Tap" "3T" Muzzle Brake / flash hider for 5.56mm projectiles. One of my earliest models, with dimensions extracted from a single sample with metric calipers. For those of you who have seen Chris Costa, and/or Jerry Barnhart running SR16 and SR15's this is the brake.