Curious about the old fashioned movie style of detonating explosives.

Hey all, I’m sure we all have seen the old fashioned way movies depict blowing up TNT, with a box and a T coming out the top, push it down, and you have your explosion, I’m wondering what that is actually called, and I’d like to learn more about how it actually worked, I’m guessing it maybe had a peizo electric material in the bottom to generate an electric charge, or perhaps a mechanism similar to the magneto in old phones.