We have been asked about this one a lot. We have been using them on our own machines for over a year now.
The Immortal Arms Stop Pedal is coated in a rubbery plastic, is plenty strong to put up with any amount of stomping. The cable is about 5.5 ft.
We include an RCA splitter so that you can attach to your AmmoBot. You can either wire it to the yellow port or on a Rev3, open the cable harness on the stop switch (at the shrink wrap) and put the splitter inline of the stop switch (this is how we do it).
We can wire the switch as a "step to stop" or as a "lift to stop/deadman".
*This item ships free*