STEELMAN PRO 79996 2-Piece 3/8-Inch Drive Spark Plug Socket Set, 5/8 and 13/16-Inch Sizes 5/8-inch and 13/16-inch spark plug socket set Constructed of durable chrome-vanadium steel Black oxide-dipped surface for added strength Serrated edge cuts and cleans broken spark plug boots Hex-shaped end allows for use of hand tools