Standard practice in the U.S.A. is to use crush washers, O-rings and/or Stat-O-Seals to seal ports and banjo fittings. English practice is to use Dowty Seals. Dowty seals are similar in concept to our Stat-O-Seals, but are considerably smaller in diameter (and thicker in cross section). Since many of our road racing and Indy cars' and their mechanics' are of English origin, Earl's offers a complete range of Dowty Seals.