Lithium polymer (LiPo) batteries are rechargeable batteries that have been used in battery-operated devices for several years. The main advantages of Valken Energy Li-Po battery cells are that they have about four times the energy density of nickel cadmium or nickel metal hydride batteries. LiPo batteries are very lightweight and pliable, and can be made to almost any size or shape. The increased higher energy density of Li-po cells allow airsoft motors to operate longer between charges than nickel metal hydride cells. Valken Energy Li-po batteries must be charged with a lithium polymer balancing charger inside and Li-po safety sack to reduce risk of overcharging and overheating.