Vintage Triner air mail scale. This one is particularly interesting as it was used and is marked U.S.A.F. S.1532. The scale was made by Triner Scale & Mfg. Co, Chicago, Ill. Model AA-4. The scale shows wear and marks. There is a bit of paint spatter on the top. A couple of the worn areas are starting to show some light surface rust. It measures approx. 16 1/2" x 7". Please pm me for additional pictures.