Considered by many to be the "normal" (and most handsome) Marx brother, Zeppo Marx appeared in only five Marx Brothers' films. Generally not the center of attention, Zeppo functioned mainly as a bland romantic distraction to Groucho, Chico, and Harpo's vaudeville-based comic craziness, and as a replacement for older brother Gummo, who left the act to pursue other avenues. Zeppo appeared in The Cocoanuts, Animal Crackers, Monkey Business, Horse Feathers, and what is considered by many to be the best Marx Brothers' film, Duck Soup. After leaving the act, both Zeppo and Gummo became very successful Hollywood talent agents. In addition, Zeppo invented a wristwatch to monitor the pulse-rate of cardiac patients that would ring an alarm if the patient went into cardiac arrest as well as clamping devices used in atomic bomb raids in the mid-'40s. Zeppo's second wife, Barbara, a former Vegas showgirl, divorced him after ten years and later became the last Mrs. Frank Sinatra.