16650 3.7V Lithium Ion High Capacity Cylindrical Battery 2.2Ah
NOW REPLACED BY 18650's (18650 =18MM DIAMETER, 16650 = 16MM DIAMETER, still the same length)
3.7V Lithium Ion High Capacity Cylindrical Battery 2.2Ah, Sanyo, 16650
Click on image for more options.
Do not attempt to charge these batteries using chargers for nickel based batteries or any charger not specifically designed for this technology.
It is important for these units that a PCM (see specifications tab) is not present in the application as these cells may not function properly.