The latest in Airsoft battery technology. Li-Fe batteries have a longer life cycle and also better performance at extreme temperatures compared to Li-Po batteries. When using batteries in Airsoft weapons, it is important to have temperature resistant batteries as some other batteries can get too hot when in use. Another thing that makes life batteries a good alternative is that they are at 9.9V. Most common Airsoft weapons cannot withstand batteries that are at 11.1V, as piston gears and other internal parts are not built to withstand that stress. A 9.9V Li-Fe battery has the perfect condition for a high-performance Airsoft weapon.