Oops, correcting an incorrect post I made earlier suggesting they were older/army: I'd forgotten what the deal with the brass ones of these were. If there is no trace of a silver finish I believe they were an early Air Force (late 40's-early 50's) "transitional period" hat device from before the Air Force switched to a blue uniform with silver tone devices (they had been using Army uniforms). http://usafflagranks.com/usaf_transitional_period_uniform.html