:This paper outlines design considerations and criteria used to construct a prototype vapor balance gasoline nozzle. The nozzle incorporates a particular magnetic material on the face of the vapor recovery boot with a synthetic polymeric material on the sealing surface. A specific vapor recovery boot design is revealed which assists mating to the surface of the fill pipe.This nozzle was evaluated on 47 in-service vehicles at a specially equipped, commercial station in Chino, California. The prototype nozzle was solely supported by the automobile fill tube. Fill pipe-nozzle interface losses, car vent losses and station vent losses are all counted in the overall performance of the system. Percent vapor control was 88.9%.The investigators suggest that a fill pipe designed for vapor recovery would routinely yield results in the high 90s.