I found myself needing to do some work on my water line this week and just could not get a good angle on the main water shutoff valve with a pair of pliers. A little while in a CAD program and seven hours later, out pops this handy little tool. Yes... seven hours. I tend to over-engineer everything.
This was printed with 70% triangle infill, 2mm walls (5 walls with a 0.4mm nozzle) and 1mm top and bottom (5 layers at 0.2mm layer height). This may be overkill, but I like things to hold up. I used supports, but depending on your printer's bridging abilities, you may not need them.
The tool utilizes a 1/2" drive for use with a standard 1/2" ratchet or breaker bar.