To remove a plug fuse, grasp it by the rim and turn counterclockwise.
2.
The about 150 exhibited items include a voice-recording watch, a encrypted documents or codebook ( block cipher ) as well as various spying equipment in the form of utensils like pen, plug fuse etc . Also bugs, detected in buildings of Turkish diplomatic missions abroad in the Cold War era between 1967 and 1989, are on display.