There are two main types of sustain pedals available for keyboards and other instruments. One of them normally looks like a small box, nearly square, and is sometimes called (and used as) a footswitch.
The other type is longer and has a silver pedal that looks much like what sticks out from the center (near the floor) of an acoustic piano.
M-Audio makes both types of pedals, calling the former the SP-1 and the latter the SP-2. Let’s take a quick look at each one. Quick, because there really isn’t much to say about a sustain pedal other than what I’ve already told you.
M-Audio SP-1 Sustain Pedal
The M-Audio SP-1 is the boxy, footswitch model. It’s intended for use with keyboards, synths, tone modules, drum machines, and the like.
The 5-foot cable has a 1/4 inch male end that you plug into the instrument. As with most pedals, it includes a polarity switch so that it will work with all brands (essentially, Yamaha or Casio) of keyboards.
M-Audio SP-2 Sustain Pedal
The M-Audio SP-2 is the acoustic piano style of pedal. The design is supposed to make it feel like the pedal action on such a piano. Of course, if you’ve never played (and used the pedals on) an acoustic piano, you’d never know whether or not this is true.
The cable is a little longer at 6 feet, though that probably will never matter. The jack end is, again, the standard 1/4 inch male plug. You can switch the polarity on this one as well.
That’s about it. As I said, this would be quick because there simply aren’t a lot of parts or features to discuss when talking about a sustain pedal. It’s really a matter of which style you prefer – the SP-1 footswitch or the SP-2 acoustic piano model.