I'll explain a bit. Basically juancho/black bear 84's lights are versions of what we (flashaholics) broadly call mag85s. Mag because we use the maglite body, '85 from the bulb we use (the welsch-allyn 1185 bulb). He also sells some other magXX mods (where XX stands for other some welsch allyn bulb numbers). In the same way that you can make a cheese and ham sandwich in many ways, the mag85 can be made with different components (batteries, battery holders, bulb holders, etc).
Basically, he is one of the better sources for the mag85s (Juancho claims to use top quality components in his lights). I don't know of too many (if any?) others who are selling mag85s on a DIYFSE kind of basis. You can make your own mag85 - it's not particularly difficult and can be great fun, but if you're looking for a "turnkey" solution, he is a good option.