This mini line mixer is complete with echo effects, delay time and depth controls, and has up to 50dB of gain per channel. It has four 1/4" mono inputs with individual volume controls and a 1/4" unbalanced output.4 Mono 1/4" microphone inputs with individual volume controls Built-in Echo Effects DSP with Delay Time and Depth controls emulate room and hall to stadium decay reverbs 1/4" unbalanced output Up to 50dB of gain per channel Power on/off switch with LED indicator, 9VDC powered with either 9V alkaline battery or optional PAD-1 AC/DC external adapter