The Slim Jim is a simple holster, even simpler than the Folder. Like the Folder, it is made from a single piece of leather folded over. The difference is, it's thinner - it lacks the reinforced mouth - but it is no less stable or secure.
It has a 15 degree cant for an easy draw from anywhere from 3 to 5 o'clock. A deeply molded channel along the front edge of the holster protects the front sight during the draw (unless like the Kel-Tec P3AT there is no front sight).
Lefty? No problem. 1911? No problem.
Customization - free (usually)
Maybe you want a crossdraw mag pouch integrated into the holster, and steel belt clips instead of the standard snap loops? We can do that, in this case with a small added expense for materials and time.