The BobWire XLR1 is a two channel(stereo) balanced XLR audio A/B selector. The XLR1 will automatically switch between two XLR inputs or one XLR input and one RCA input and send the audio signal to one XLR output. The Input B XLR/RCA switch determines if Input B will be balanced(XLR) or unbalanced(RCA). The Mode switch determines whether the XLR1 will operate by audio sensing or by a 12V trigger input signal.