For safety reasons, the German army was naturally reluctant to use percussion igniters. On this model, the striker spring is relaxed until the moment of ignition, reducing the chance of accident. The striker is integral in a tube terminating in a mushroom shaped head held in place by a ball. The tube lodged in the igniter body has a spiral guide surface which, in order to extract, requires a twist pull movement, preventing accidents. When the tube is twisted and pulled, it raises the striker which compresses the spring until the point where the ball, rising from the top of the igniter, falls out. The striker, suddenly freed, explodes the primer. Using a percussion igniter presented an advantage, along with some risk, causing a rapid increase in the use of this igniter. Overall, this igniter provided no real advantage over the pull model due to complexity of construction. Invented at the end of 1916 it was abandoned by thr start of 1917. the ones made in 1917 are recognizable by the absence of any brass parts. Used on Kugel and Egg grenades.