The Do 17 Z-7 was a model of the Do 17Z, the main variant of the Dornier Do 17. The Dornier 17, dubbed the "flying pencil", was designed in the early 1930s and was mainly used against Poland, England, France and the Netherlands. In total there were 2,139 built. Other countries that used the Do 17 were Yugoslavia, Finland, and Spain. Only a few Do 17s remain today, none of which are of the Z-7 model. The primary model, the Z-2, was designed as a "Schnellbomber" ("fast bomber"), intended as a light bomber able to outrun enemy fighters. Its offensive armament was sparse, consisting of only two MG 15 machine guns mounted in a glass nose. The Z-7, however, was built as a night fighter, and as such was up-armed with MG 17s. The glass nose that characterized earlier models of the Do 17 was replaced with metal armour. The clustered three-machine gun, single-cannon configuration the Z-7 boasted was known as "Kauz I" ("screech owl"). It was with this weaponry that the Luftwaffe intended to take down enemy bombers, and the Z-7 was in use as a night fighter all the way up to 1945, due to its greater success as a fighter than as a bomber. Do 17 production ended in 1940, supplanted by the Ju 88 and succeeded by the similar, but more powerful, Do 217.