The artwork depicted in this bulb is that of Robert Crumb. During the 1970s, Crumb headed the underground comics movement and produced some of the most memorable comic art in recent times. Undoubtedly his most well known work that permeated the mainstream conscious was the Keep On Truckiní art made famous during the 1970s. This bulb is known to exist in slightly different variations as well as other envelope shapes. This bulb does not appear in any vintage Aerolux or Duro-Test literature in the authorís collection and it is unclear how the bulb was originally distributed.