ART Headamp 6 Pro - 6-channel stereo headphone amplifier with separate bass & treble controls, front & rear panel outputs, XLR & 1/4" balanced inputs. Operates in Stereo, mono (source left), mono (source right) or summed mono (source left & right), auxiliary front-mounted separate source input, 8-sement LED level indicators on all channels & bus. Dimensions: 19"/1U