Im sure this wont be super popular as its kind of specialised, but maybe someone will be able to use it, it is a life saver for me. The coolant reservoir tank on my 2008 freightliner cascadia series 60 detroit 14l is unbeleivably hard to remove as the rubber gasket under it swells and makes it imposable to remove without beating it unmercifully with whatever random object i have in my pocket at the time, usually a pocket knife. This tool solves that problem and it only took me about an hour to design and print. make sure you give it some heft with lots of walls and fairly high infill.