The Rolls PM351 is a mixer designed to make the lives of studio and stage musicians a little easier, specifically by allowing musicians to monitor and control their own levels. If you're a drummer who needs to monitor a click track on stage, or a guitarist who needs to turn down the vocals in the mix, this device is suitable for you. 

Input jacks are provided for instruments, line-level sources, and microphones. By means of three independent volume knobs, you can tweak the level of all three signals, and give yourself the best balance. A 1/4" output and balanced XLR thru-put facilitate connections to mixers, recorders, PAs, and more. Headphone outputs are also on hand, one for 1/4" connections and another for 3.5mm terminations.

While the PM351 can support signals that require phantom power, it does require an independent power supply to run. It will not run off phantom power from consoles—that's why the power supply is included.