Great find, Tiny!! There is also this non-twist style. These are also great for holding the brake pedal while you check your brake lights, and sometimes great for holding the gas pedal when you need to hold a higher RPM. In California, fleet diesels are held to a 5 minute idle rule. Sometimes, as a mechanic, you don't want that thing shutting off on you after 5 minutes. So you use the prop to hold the pedal off idle until you are done with your work.
