8.4v 2400mah Inertia Generator Crane Stock Battery (NiCd) This custom battery pack is constructed of eight cells in a crane stock style configuration, it is made of Nickel Cadmium. This means several things in electrical and airsoft terms. The first is that the power output is only 8.4 volts, this makes it perfect for non-upgraded guns such as Tokyo Marui, but a little under powered for some like the 2009 edition Classic Army's. The capacity on the battery is 2400 mah, which translates into about 2400 shots (maybe as much as 2800) before the battery loses charge and needs to be put on another cycle. The second affects charging cycles. NiCd batteries have to be discharged before they can be charged during a typical charging cycle. If you don't discharge and instead just try and "top it off", the battery will eventually develop a memory like the older cell phone batteries. But this seeming deficiency is also a big positive in other areas. NiCd batteries are able to hold their charges longer during periods of time when they are not being used. They can also go through more charging cycles before loosing efficiency, on average about 450 versus the 300 that most NiMH batteries get. This battery fits best in Crane Stocks such as the ones found on the Classic Army M15A4 PMC and M15A4 CQB Compact SEAL. Note: This battery must either be drained completely or discharged before being put on a charging cycle. Failure to do so may result in recrystallization and the eventual development of "memory". (Memory is bad!)