Hitachi BSL1815S 18V Lith-Ion Battery These batteries are 18-Volt Lithium Ion at 1.3-Amp Hour Has three times longer battery life and half the weight of Nickle Cadmium or Nickle Metal Hydride Maintains a steady level of power throughout charge Authorized Hitachi Dealers provide the full Hitachi Warranty Charges in 35 to 60-minutes