NEW LOCKING CHROME GAS CAP, COMES WITH 2 KEYS, FITS 1960 TO 1966 CHEVY OR GMC TRUCKS. It measures almost 2 1/2" od, 1 1/8" tall and with a 5/8" chrome lip. The inside that goes in the neck is 1 1/2" od and it is 1 3/4" to the outside of the tabs. It is built for a 2 1/8" gas neck.