This casemate was partially destroyed by US Army engineers in trials they undertook to find the most efficient way of of destroying these emplacements. Under the previous owners this housed one of the guns of battery "Blankenese" near Néville sur Mer on the Cotentin Peninsula. This battery was manned by 2/260 Marine Artillerie Abteilung of the Kreigsmarine. It was armed with 4 captured British Vickers QF 3.7 inch AA guns. It was captured on the 20th of June by the 24th Cavalry Squadron, VII US Corps
http://en.wikipedia.org/wiki/QF_3.7_inch_AA_gun