The ABI Balanced Line Input Switcher from Palmer provides level adjustment of microphone or line signals. By toggling between the two inputs, the input permits signal comparison and connects the two sources to a single input. Three slide switches select 15 dB of attenuation for input A, and 6, 15, or 21 dB for input B. A ground-lift switch eliminates the earth-loop hum and a red LED indicates the active input. The switcher features a solid metal casing with extended edges for protecting the inputs and outputs. Pre-drilled holes can be used for mounting the unit into a rack or onto a pedalboard.