This is referred sometimes as an on-on-on switch, meaning in any of the 3 positions it is always on. In one position you turn on the upper E9th. neck, in the middle position you turn on both the E9th. and the C6th. neck and in the lower position you just turn on the C6th. neck.

1 Mullen steel guitar neck selector switch. This is the same switch that come on their new G2 guitars.

The switch selects the upper or lower neck or in the middle position turns on both necks.

A real quality sounding switch that is small and out of your way when playing guitar.