The Whirlwind PB12 is a passive press box microphone output expander, housed in a rugged steel case, for Whirlwind's PRESSPOWER 2 and PRESSMITE active press box line outputs, or any other live press conference or forum application where a line level feed is available. It is intended for broadcast and commercial conferencing applications. The PB12 distributes one line level input to multiple mic level outputs. Each output is transformer-isolated, providing superior interchannel isolation and ground lifting, helping to noise problems. Whirlwind's own TRSP-2 transformers are used throughout. 1 to 12 line in/microphone out passive press box expander for broadcast and business conference applications Rugged, all-steel housing with convenient carrying handle Transformer isolation and grounding for each output eliminate interchannel and RF noise