The PM50se mixes a stereo or mono line-level Monitor signal with a microphone or line level XLR signal to a set of headphones. It has a monitor level control, mic/XLR level control, mic/line pass through XLR jack, two headphone output jacks, and a stereo or mono TRS or TS 1/4" monitor input jack. Possible users may be drummers who need to hear a click track, choir singers who need to hear themselves, podcast, recording or many other applications. The power adapter is included.