This is Gemtech's shortest and lightest HALO to date. The closer mechanism is improved for use on the standard A2 birdcage style flash hider blank firing adapter groove. It is also compatible with the Primary Weapon Systems KAC556 mount.
Weight: 12.2 ounces
Mount: 5.56X45 Universal, Fits A1/A2 Flash Hiders, includes shim kit - See more at: https://gemtech.com/gmt-halo.html#sthash.CAyE2GHb.dpuf