For connection of film projectors, tape recorders, and phonographs to standard low-Z balanced microphone input of public address system. RCA, 1/4" (6.35mm) and mini-jack (3.5mm) inputs. Male XLR-type balanced mic-level output and unbalanced 1/4" line-level output. Switches for high/low level attenuation, 16 ohm load, and ground lift. Uses Pro Co DBT-1 transformer (20k/150 ohm). Picture shown above is AV-1 the AV-1A has 2 RCA inputs.