This five-channel headphone/earphone distribution amplifier offers a variety of input options, giving you four master mix inputs. Four separate mixes can also be monitored using the main inputs and the three Insert jacks on Channels 1, 2, and 3. You also get a JOIN Input/Output 1/4" jack for connecting two units together to give you up to 10 channels of headphone monitoring. Each channel has a Level control, a stereo 1/4" Output jack, and a 1/8" (3.5mm) Output jack. It has plenty of gain for operation in noisy environments, and works with most any headphone impedance. Includes PS27 universal power supply.