This thread is more specific: why do so many people object to Tomb Thumbs and dislike them?
(worth a read)
Argentine snaffle, misnamed, of course, because it's not a true snaffle at all. Due to the size of the "Pelham" rings, I wouldn't really recommend attaching the reins there for long periods of time. It doesn't provide the greatest cue. But the width of mouthpiece is pretty typical (and not harsh).