SK 4492 2 Piece 3/8-Inch Drive 5/8-Inch and 9/16-Inch Flex Spark Plug Socket Set Corrosive resistant and laser engraved every 120 SureGrip hex design drives the side of the fastener not the corner Innovative swivel socket design gives great access. Durable rubber retainer holds spark plugs by the porcelain insulator for better grip. Made in the U.S.A Lifetime Warranty