1200rd Drum Magazine. Fits most of the M4/M16 series excluding Tokyo Marui Next Gen. BBs are fed electronically via help of NiMH battery or 3 x AAA batteries. There are two options available for the feeding. The first one is always feeding with out any touch of a button etc. The second way is via sound activation which operates when the gun is fired upon, the magazine will feed automatically the BBs due the sound/noise of the gun.
The package contains a separate battery, USB charge cable and housing for regular AAA batteries.
Batteries do not come with the magazine.