... .7v for GPS Tracker, LED, portable instruments, kinds of meters, PDA etc.1) 3.7V 18650 size Cylindrical Li-Ion Cell2 ... :GPS Tracker, LED, medical devices, kinds of meters, portable instruments, PDA, Power tools, miner's lamp, Audio and Video Devices, Information ... or fracture the cells. Do not directly solder the battery cell and pierce the cell with sharp objects. Any different voltage and capactiy ...