Also known as "Battery OD", it is located only a short trip south-east of Oxelösund on the Swedish east coast, and is blasted into the rock on the Femöre peninsula.

[1] The battery was part of a series of similar facilities built during the 1960s and 1970s as a defence against potential attacks from the Soviet Union.

Battery OD was the third of a total of 30 forts built in Sweden during the Cold War.

Due to a local interest group, large parts of the fort were instead preserved and is today used as a museum.

The armament consisted of three 7.5 cm tornpjäs m/57, with an effective range of 13 kilometres (8.1 mi).