This is our 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. - Caliber: 5.56mm - Sound Reduction: 29dB - Diameter: 1.5 - Length: 7.2 - Weight In Units: 12.2oz - Mount: 5.56X45 Universal Fits A1/A2 Flash Hiders includes shim kit - Material: Titanium - Full Auto Rated: Yes - Finish: High Temp Black Cerakote