The new 2016 Caldwell Accumax AR-15 Barrel Cooler, engineered by Battenfeld Technologies, Inc. is a must have for any high volume AR shooter. It is perfect for competition shooters, full auto shooters and varmint hunters. It locks into your Mil-Spec mag well using the magazine lock. It then has a high performance fan that forces cool air through the chamber and directs it down the barrel of your AR-15 drastically decreasing cool down time. Complete with a 12v. Li-ion rechargeable battery means that your fan