An improved electric plug for automobile use is equipped with an extra extension cord sticking out of a side hole; and a cord fixing hook disposed at the periphery of the top end of the plug body; and a socket disposed at the top end of the plug body so as to permit another plug to be coupled thereto...http://www.google.fr/patents/US5326283?utm_source=gb-gplus-shareBrevet US5326283 - Electrical plug for automobile use
