Bellows [1]

Balance Stage II vapor recovery [2] nozzles must make a vapor-tight connection with the fill pipe of the vehicle tank that is being fueled.

The bellows device is used to provide this tight connection is an accordion-like sleeve, made of a flexible rubber or plastic compound, that fits around the outside of the nozzle spout [3]. When the spout is inserted into the fill pipe, the folds on the bellows compress, and the end of the bellows mechanism forms a snug, vapor-tight union with the lip of the fill pipe.

The bellows is also referred to as the nozzle boot [4] or boot assembly.

See also Nozzle [5].