These are reproduction o rings that I have used on my own G M cars.They seal the filler tube to the gas tank.They are a tight fit, so I used some rubber lube. A dull tool may be needed to push o ring into place beside the tube. A nice tight fit. Thanks!! P S These fit most GM cars from 1957 to 1964. Due to our slowing of our mail service, Please allow extra delivery time!! Thanks!!