Double-Up only had one comic book appearance, which was in a one-shot 1941/Golden Age comic series wherein a different hero had one issue. He has not appeared since and is in the Public Domain.
Double-Up has not appeared in any comics since his introduction in the Golden Age.
Powers & Abilities
Double-Up was a war-hero and was in peak human shape, and was an experienced hand-to-hand fighter. He had a costume that was inferred to protect him from damage.