The Valken Battery Tester is a great personal item to have to make sure your battery pack is still game ready after countless number of uses! The airsoft battery tester can quickly check the remaining charge of various NiCd, NiMh, LiFe, LiPo, and Li-Ion airsoft battery packs. It's easy to read digital display lets you know at a glance if your airsoft battery pack needs to be recharged. The battery tester also displays the voltage of each cell, so you know when the battery pack needs to be balanced. It can also display the internal resistance of each individual cell, so you can evaluate the health of your battery pack and decide when to discard or replace it.