Specifications: Input Voltage: 1.2-18V Input Current: 0.8A Output Voltage: 27V Output Current: 1.5A (1-7cell) /1A (8-15cell) Color: Black CE, FCC and RoHS certified. Plug: UK Fit for: FESTOOL: 497019, 498336, 498338, 564247, 398338, C12, C12LI, T12+3 and identical batteries,These batteries are e.g. used in the following devices: FESTOOL: BPS12C, BPC12, BPS12S LED Indication Light: Red: charging is running Green: charging completed, battery full Flashing red: bad connected, high temperature or reverse connect If your battery getting too old and cant take a charge or can not run after charge, then you need a new battery, not charger problem. Note: Only suitable for Ni-MH,Ni-CD battery. Indoor use only. Make sure the charger connectors are matching the battery before using.