The picture shows this 1939 - 1940 New York World'sFair Advertising Bookmarker. The bookmark appears to be made of stainless steel holding a small Fairmedallion. The medal has the Trylon & Perisphere with the Sun in the background. It reads
"NEW YORK WORLD'SFAIR"
It measures 3-5/8" long and is in excellent to near mint condition.