When it comes to "pad-based triggering," the AKAI MPD16 is the one for me. Its portability, the quality of the pads, and its stable, long-lasting performance with a mobile battery made it a hero in my living room. I've lent it out and left it in various places (and retrieved it!), and even had some in the barn. I've listed several recently, but I still have two more, so I'm listing them. Operation has been confirmed with both an AC adapter and USB bus power. The body still has the protective film on it, and there are no noticeable scratches. The AC adapter is included with the main unit.