The lapel pin was a communications badge that was used by S.H.I.E.L.D. agents.
When Nick Fury asked J. Jonah Jameson for help tracking down the Chameleon, he gave Jameson a lapel pin with the S.H.I.E.L.D. logo on it. Fury then told Jameson that the lapel pin was really a communications badge and that if he were to see anything suspicious in the Daily Bugle to tap the lapel pin and it would alert S.H.I.E.L.D. agents in the building to his location.