The Morley A/B/C Box is pedal that allows you to send one signal to three places or three signals to one place. The most practical application of the A/B/C box is for use with electric guitar and sending one guitar to three different amps, or vice versa if you want to send three guitars to a single amp. The box has got 1/4" connections for in/out, which is your main connection, and then three more connections for your A, B, and C channels. Each channel has it's own switch on the one that I've used, but there are a few different versions as the one pictured above isn't the same as the one I've used, which is blue and not black. The only real difference that I can see is that on the one I've used, which is the newer one, it's got individual switches for each channel while the older one only has two. It definitley seems like the newer one with it's own individual switches is easier to use, but I'm sure it costs a bit more as well since it's newer even if you were to compared used prices. The Morley A/B/C Box has practical use both in the studio and on the stage, but is probably most useful for live shows where you have multiple guitars or amps. There are a lot of different A/B boxes out there, but there are definitely less A/B/C boxes available, at least in what I have seen. I can't say that I've ever used another A/B/C box, although I've used a bunch of other A/B boxes. It really just depends on how many channels you need, but if you think you need an extra channel I'd definitely recommend keeping the Morley A/B/C Box in mind as it is well built and will definitely do the job for anyone who needs something like this...