The PARD Li-Ion 5000MAh, 3.7V 21700 rechargeable battery is designed to be used in select PARD devices. No longer do you have to worry about a dead battery in the field that requires that you go home to charge your device. Now you can simply replace a dead battery on the spot by replacing your dead battery with a fresh one. Carry several batteries in your pack to ensure that you are never left without the Night Vision or Thermal support you have come to depend on.