Fischer Amps Mini Body Pack XLR AAA Batteries and the capacity can be

and the capacity can be increased

Precharged cell

Includes 2 USB ports for charging smartphones

But probably the best feature can't been seen by the naked eye

Fischer Amps Mini Body Pack XLR AAA Batteries and the capacity can beThe Mini Body Pack is a brilliant tool for use with headphones or in ear monitoring either live or in the studio. It is fixed at a belt with a clip. The cable coming from the headphone amp is plugged in the bottom side of the Body Pack and is locked to avoid that it is inadvertently pulled out. A 1 8" stereo plug for the headphone or the in ear earphone as well as a passive stereo volume control are at the top so that the volume can be controlled