me 2 - been using touch up guns just like that from Northern and other places. and painted about 5 motorcycles with them.
Its a schlock up of a binks detail gun and works very well, especially with the current paint formulations that are designed to be used in an HVLP. One note though, you get a big paint fog, so make sure (especially in slow drying colder temps) that you cover everything else you don't want painted, because overspray will go everywhere.
I found one in a pawn shop once and they wanted $49 for it and I said you are crazy I can go (literally) next door and get one new for $20. They just looked at me like I came from another planet.
Getting harder and harder to get a deal at a pawn shop these days - they think they are sears.