... Longer storage life than NiMH Batteries li-ion battery pack 3.7v for GPS Tracker, LED, portable instruments, kinds of meters, PDA ... batteries produce 3.7 volts.2. High energy density.3. Long cycle life4. Minimal self-discharge, less than 10% monthly. ... experiment, with acupuncture, smash, drop, and so on.Product Application:GPS Tracker, LED, medical devices, kinds of meters, portable instruments, PDA, ...