The Wechselapparat M1917, also known as the Wex, was a lightweight flamethrower developed from the Kleinflammenwerfer M.16 ("Kleif"). It was, along with several other flamethrowers of the era, developed by Richard Fiedler, as early as 1901. Fiedler's designs were formative to flamethrower technology and analogous designs remained in use for many years.