Military clutch pin or also known butterfly clutch pin, has two components i.e. the first component is a post with pointed tip, about half of a millimetre in thickness and about 10 millimetres high. The post is spot welded to the back of the metal badge. The second component is a round brass disc approximately 10mm in diameter with 2 small flaps that you can pinch with your index finger and your thumb to release its grip from the post.
Another pin type fastener is called Tie Tac or of deluxe clutch. It also uses a post, it is a better quality fastener, the post is taller at 12mm high. These Good quality clutches will not loosen its grips over time. It has a spring mechanism built inside the clutches. It is a small bulb-like structure at the top and a base with flange. To open or release the clutches from the post, one needs to pull the small bulb with one’s thumb and index finger.