Rin Tin Tin was much sought after and was signed for endorsement deals. He was featured in ads for Ken-L Ration, Ken-L-Biskit, and Pup-E-Crumbles. Warner Bros. got thousands of requests for publicity photographs of Rinty, which were signed with a paw print and a line written by Duncan: "Most faithfully, Rin Tin Tin." In the 1920s, Rin Tin Tin's success for Warner Bros. inspired several imitations from other studios looking to cash in on his popularity, notably RKO's Ace the Wonder Dog, also a German Shepherd dog. Around the world, Rin Tin Tin was extremely popular, because as a dog, he was equally well understood by all viewers. At the time, silent films were easily adapted for various countries by simply changing the language of the intertitles. Rin Tin Tin's films were widely distributed. By 1927, Rin Tin Tin was the most popular actor with the very sophisticated film audience in Berlin.