Measures 0.50” Diameter Our pins are die struck from jeweler's metal, soft enamel color filled, and epoxy coated. Pin fastens with what is known as a butterfly clutch which is one of the most popular modern methods of attaching pins, also known as a military clutch. The back of the pin has a small prong attached and when the butterfly clutch is squeezed and pulled up from the prong the pin is released from the clutch.