Gray Ops CNC Chamber Flag - Left Hand Action Black. Prevents mags from being inserted unless the flag is removed and the ability to add a chiller on those hot days Specifications for Gray Ops CNC Chamber Flag - Left Hand Action: Manufacturer: Gray Ops CNC Color: Black Last Chance: Yes Features of Gray Ops CNC Chamber Flag - Left Hand Action Detects round left in chamber. Prohibits AICS magazines from loading when flag is in place (AW mags when bolt is pulled back). AICS magazines must be removed for flag to go into chamber (AW mags when bolt is pulled back). Prevents leaving magazine in rifle when flag is inserted. One hand insertion and removal. Fits short actions. Push to forward position and use with portable air pump for barrel cooling. The cooler is rechargeable via USB - approximate 15 min run time it is recommended to connect a small USB battery pack to recharge while not in use. For cooling barrel in vertical orientation place one side of elastic over windage knob to hold bolt forward. Package Contents: Gray Ops CNC Chamber Flag - Left Hand Action Gray Ops CNC GO-CMIL: Chamber Flag - Left Hand Action Black