Abstract: A bottle cap is manufactured including a base cap and an integrally molded overlayer and gasket combination. The base cap is formed of a first material and includes at least one aperture passing through the base for the formation of the overlayer and gasket. The overlayer and gasket are formed by injecting a second material over the base cap and through the aperture. In particular, the overlayer is molded onto at least a portion of an outer surface of the base cap, while the gasket is simultaneously molded through the aperture, to form a sealing gasket on an underside of the base cap, integrally connected to the overlayer. The base cap and the gasket are constructed and arranged to cooperatively seal an opening of a fluid container.