I hastily bought something on Ebay and now that I have it am not sure what to do with it. It was advertised as an "A/B switch" but there are no input jacks on it, only a line out with a 1/4" plug. It's a small black box, about 6" x 4" and 1.5" deep with four rubber feet. By one foot switch there are two lights ("A" and "B"), and by the other switch is one light (the printing by it is illegible).
Any idea how this is supposed to be used, or with what? Thanks.