Hitachi Power Tools 326241 18-Volt Lithium-Ion Battery: * 18-volt lithium-ion battery provides 3.0-amp per hour and weighs 40 percent less than Ni-Cad or NiMH batteries * Three times as many charges cycles as Ni-Cad batteries * 25 percent more run time per charge that Ni-Cad batteries * Can be used with Hitachi Ni-Cad and NiMH tools * Overcharge and overdischarge protection to increase the life of the battery * 1 year warranty