Pre-charged and ready for immediate use. Can be recharged up to 500 times. Batteries maintain 75% of charge after 1 year of non-use. Provide high performance in sub-zero temperatures to -4 degrees Farenheit. No memory effect; a full charge every time,Nominal Voltage: 1.2 V. Size: AA 14.35x50.4 mm. Weihgt: 30 gr.