You’re looking for a sport climbing harness, they’re light, simple and pretty cost effective. They have a single adjustment on the waist belt and no adjustment on the leg loops (you don’t need it) and a few gear loops.Simply grab a harness, tighten it up so that you can slide your hand between the harness and your belly, but not bring it back through once you’ve formed a fist. Easy!Good stores will have a setup to let you hang in the harness to get a better feel for which style is most comfortable.