input: 3.5mm RCA connector, 6.3mm Link output: 4 x 6.35mm JACK Stereo S/N ratio: >98dB input Impedance: 1kΩ (Unbalanced) output Impedance: 10Ω min. each channel max Output power: 4 x 100mW power supply: 12-18VDC adaptor indicators: Power Led4CH channel headphone amplifier with independent gain controls. It can power up to four pairs of headphones and up to four independent volumes. Ideal for virtually any home or project studio. The X4BOX easily adds additional headphone outputs to any mixer, computer audio interface, workstation, iPod, media player or laptop without creating any additional load on the existing headphone source. RCA input with 6.35mm Link, 4 x 6.35mm Jack outputs, Stereo/Mono switch and 12/18V AC adapter included.