Acroprint ES900 Full Power Reserve Battery (Atomic)Default ManufacturerAcroprint ES900 Full Operational Ni-Cd Battery for punching when the power is off, up to 200 punches. For AtomicOffice Suppliesacroprint-es900-NiCd-battery-atomic58-0108-00070.80Time Clock Expresshttps://www.timeclockexpress.com/Item/acroprint-es900-NiCd-battery-atomic