Brand New, never used, in perfect condition but open box item (without manual but includes power supply).

Behringer product info:

Ultra-Compact 4-Channel Stereo Headphone Amplifier

If you're tracking more than one musician at a time, or if everyone in the group wants to listen to the playback, you’re need a monitor distribution system. A distribution system allows everyone to listen in, and control the volume of his or her own headphones. The compact and flexible HA400 can power up to 4 pairs of headphones and up to 4 independent volumes, with outstanding audio quality – even at maximum volume!

You can use this super-compact stereo headphone amplifier with practically any headphones – four of them at the same time, to be exact! Let up to 4 different people in your studio listen to the main mix while recording, and each listener can determine their own preferred volume level using the dedicated output level controls. The HA400 contains 4 high-power stereo amplifiers that maintain the highest sonic quality even at maximum volume levels. Ultra low-noise 4580 operational amplifiers are employed for outstanding audio performance – these are the same op amps found in “full-size” audio equipment – plus, a dedicated 12-Volt DC adapter is included.

    Ultra-compact headphone amplifier system for studio and stage applications
    4 independent stereo high-power amplifier sections
    Highest audio quality with virtually all types of headphones even at maximum volume
    Phones Level control per channel
    DC 12 V adapter included