1.25” showing driver leaning from his cab window and giving the victory sign with his left hand as he steers with his right. Upper rim reads “U.S. Truck Conservation Corps” while lower rim reads “Cooperation Mack Trucks, Inc.” Text on red is “I Am Pledged To Keep ‘Em Rolling.” Button is c. 1943 and apparently issued as part of a government sponsored program which ran print ads headlined “Have You Signed The Pledge To Keep Your Trucks Rolling – Longer?” Scarce and Exc. Displays Mint.