Abstract: A universal plug is provided for electrical connection with a receptacle having a configuration selected from a plurality of different configurations such that a conventional electric plug that mates properly with a receptacle having a first of the configurations is prevented from mating properly with a receptacle having a second of the configurations. The universal plug is formed with a first plug component and a second plug component, the first and second components being separable from each other so that each can be manipulated independently of the other for electrical connection to the receptacle. The universal plug will thus mate properly with a receptacle of the first configuration and will also mate properly with a receptacle of the second configuration.

Abstract: A resealable pressure vent for a container such as a battery container having a wall containing an aperture connecting the interior of the container with the atmosphere comprising a cover member in the form of a metal plate which is spot welded at its center to the center of the wall of the container. The aperture is located in the wall away from the center thereof and an elastic O-ring is interposed between the metal plate and container wall such that the O-ring seals the aperture from the exterior of the container. In the event of excess pressure within the container, the O-ring is displaced by the said excess pressure to vent the container and the O-ring returns to its original sealing position when the excess pressure is relieved.