Heritage Audio Baby RAM, Passive Desktop Monitor Controller, 24-Position rotary switch with 0.1 dB for each individual attenuation level, Mono / DIM / Mute button, 4 Line inputs: 6.3 mm jack (2x stereo) balanced (unbalanced, switchable), 4 Line outputs: 6.3 mm jack (2x stereo) balanced (unbalanced, switchable), Does not require a power supply, Dimensions (W x H x D): 180 x 58 x 250 mm