Atop these mighty flak towers, primarily the G-towers, there were a variety of anti-aircraft guns. Mostly large caliber but some small caliber as well. These guns had the ability to fire up to 8000 rounds per minute and could range out as far as 14km around its walls. Among these guns were 37mm and 20mm cannons and the universally feared 128mm Flak 40. With the Flak 40, the Germans did not focus on making direct contact with allied air craft. Instead, they employed a technique in which they would fire these weapons in close proximity of the air craft, causing explosion of debris in the area, propelling shrapnel into said aircrafts. This technique was commonly referred to as the “Flak Window”. The kill radius for this technique was anywhere
