Lot of four from a set of 12, each is 2.5x3.25" on thin glossy paper stock. Issued to promote the 1936 film serial based on the Ace Drummond comic strip drawn by Clayton Knight and written by Eddie Rickenbacker. Similar sets were issued for Flash Gordon, Buck Jones and Wild West Days serials. These cards were mostly likely passed out on a weekly basis by theaters showing the films. Fronts feature photos of actual aircraft (courtesy of Eastern Air Lines Inc.), backs have plane specs along w/serial promotion. Cards are "Curtis Condor, Curtis Jenny, Liberty, Lockheed-Elektra." Minor handling wear visible in reflected light on two, EX while other two are NM. All of these serial cards are rare, in particular this may be the rarest set as these are the only examples we've ever offered in our 48 years from the Ace series.