In military history, the German term Kampfgruppe (pl. Kampfgruppen; abbrev. KG, or KGr in Luftwaffe usage during World War II, literally "fighting group" or "battle group") can refer to a combat formation of any kind, but most usually to that employed by the Wehrmacht of Nazi Germany and its allies during World War II and, to a lesser extent, of the German Empire in World War I. It also referred to bomber groups in Luftwaffe usage, which themselves consisted of three or four Staffeln (squadrons), and usually (but not exclusively) existed within Kampfgeschwader bomber wings of three or four Kampfgruppen per wing. The Kampfgruppe was an ad hoc combined arms formation, usually employing a combination of tanks, infantry, and artillery (including anti-tank) elements, generally organised for a particular task or operation. A Kampfgruppe could range in size from a company to a corps , but the most common was an Abteilung (battalion)-sized formation. Kampfgruppen were generally referred to by either their commanding officer's name or the parent division. The Stormtroopers (in German Stoßtruppen, shock troops, literally "punch/push troops") were specialist military troops which were formed in the last years of World War I as the German army developed new methods of attacking enemy trenches, called "infiltration tactics". Men trained in these methods were known in German as Sturmmann (literally "assault man" but usually translated as Stormtrooper), formed into companies of Sturmtruppen (Storm Troops). Other armies have also used the term "assault troops", "shock troops" or fire teams for specialist soldiers who perform the infiltration tasks of stormtroopers. With respect to their ad hoc nature and objective-oriented strategy, Finnish ski troops employed during the Soviet-Finnish Winter War of 1939-1940 could, in principle, be considered to be an equivalent to Kampfgruppen. However, given the poor equipment of the Finnish forces, the combined-arms aspect of the Kampfgruppen could not have been applied.