Supplied with some models at H & K, this switch allows you to:
(1) changing the channel 1 / 2,
(2) change of mode A / B,
(3) effect bypass / loop.
Basically: the (1) allows you to change between the clean channel and overdrive channel, the (2) allows you to change between clean and crunch of distortion between the light or soft or hard overdrive channel. The (3) allows you to enable or disable the reverb of the amp, and / or the effects loop after the fawn you set your amp faade.
Conection in DIN. Non-removable cable (I do not know the length, but I never bothered by the lack of t over). An LED indicates switch above each person or persons who are engaged. In short, use trs trs simple and intuitive. In addition it's Casing mtal everything more stable and strong! From H & K so: solid and practical!