Kis was the name of a Polish machine pistol from the time of the Second World War. It was designed and manufactured by engineers in Jan Piwnik's "Ponury" ("Grim") guerilla unit that was operating in Holy Cross Mountains region. It was probably the only kind of modern firearm that could be manufactured in the forest without the need for sophisticated tools and factory equipment until the Vietnam War, when North Vietnamese blacksmiths copied American firearms.

Knock intensity sensor