Edit: I added a solid Piston for people that don't want to add the magnet.
Never lose your keys again with this little magnetic keychain shaped like an engine piston.
Use it to keep your keys where you can find them again.
Stick them on the fridge or your toolbox or anything else metal.
Never lose your keys again!
Just print the file, assemble it and insert one 10mm diameter magnet (3 or 5 mm thick) in the piston head and presto!
Magnets needed: https://www.amazon.com/VSKIZ-Refrigerator-Muti-use-Neodymium-Whiteboard/dp/B0BVY5VYQY
For real motorheads and gasmonkeys.
Also works as a nice refrigerator magnet of course!