ts Suntour mounteck? prob an add on? dont know? but it works sweetly! Well if it works, then don't worry about it...I just recall Suntour fans slagging off on this particular rear derailleur (Mountech with huge jockey pulley) as their worst design, but others may just love them who knows! Anyway, it's made to wrap a LOT of chain, so it's not working at all on that little rear cluster. The Huret is designed for a triple, so that's a fairly good choice for the triple crank you have...I'd guess that this bike came with a touring set-up when new and probably used a Huret Duopar in the rear. Nice bike, probably a 531 main triangle and fork blades and likely a tourist...I'd rotate those handlebars UP a bit