The Hitachi EBM1830 18-Volt Lithium-Ion 3.0 Ah HXP Battery features the revolutionary Hitachi HXP Lithium-Ion technology. This advanced technology delivers a battery that is 50-percent lighter than an average NiCd battery, with a longer overall battery life and a longer run time than any other technology on the market. The HXP battery features a specialized internal circuitry system that is equipped with a current interruption and detection system, thermal protector, and an electronic switch to protect the battery against overcharge and discharge. Hitachi built this battery to be backwards compatible (it works with the DMR and DVF3 series of 18-volt cordless tools), and since the HXP battery is built on the 18-volt platform -- the core of the cordless market -- it prevents users from buying a whole new voltage platform