The HV6 (headphone volume) is designed to attenuate stereo headphone signal levels. Since the unit is passive and requires no power, it can go anywhere in a headphone level signal path, and does not need to be located near a power source. The HV6 features 1/4 Tip-Ring-Sleeve and Stereo(XLR type) inputs, Outputs are 1/4 Tip-Ring-Sleeve and 3.5mm.