A six-head wrench with heads designed to correspond to sockets in fuel tank caps.
A wrench matching this design bears the marking "Oil Trades Supply Co. Newark NJ 482-4635." It is not clear if this is a manufacturer or distributor.
Patent nos. 6,271, 1,717,241, 2,445,905 and D156,354 are cited as references. Patent D160,645 is a parallel four-head design.