The NGK BPR6EFS standard plugs come pre-gapped as specified by your engine manufacturer. It is always recommended to check the gap before installation. Use only the spark plug listed in your engine owner's manual. Using the wrong plug can reducing optimum performance, reduce fuel economy or cause damage to your engine. Spark plugs are easy to change with common spark plug sockets. The NGK pure alumina silicate ceramic insulator provides superior strength, reduces breakage and better heat transfer. The Ribbed Suppressor Seal extends resistance and prevents spark “flash over” and misfire plus the triple seal helps prevent leakage.