8.4V 36mAh Intellect Brothers Large type Nickel-Metal Hydride (Ni-MH) battery pack. Large Tamiya connector for use with compatible electric guns. High 30Amp peak discharge rate for excellent performance for stock and upgraded AEGs. * For best results, charge Ni-MH packs ONLY with Peak Chargers using Delta Peak detection compatible with Ni-MH cells!!! Incompatible chargers WILL damage your battery! ** "Dumb" chargers or constant rate (trickle) chargers which do are not compatible with Ni-MH batteries, or which do not have an auto-cutoff feature will cause permanent, irreversable damage to Ni-MH battery packs.