Your necklace will be made in this style, or in any of the styles you see on this page, and will be ready to ship within one week. The spark plug is authentic, used, and thoroughly cleaned up! The chain is appropriate...industrial style ball chain with the traditional clasp, whatever length you'd like. Most people want it between 20 to 24 inches. Your choice! Make sure you give me your email address if you're interested, so we can discuss which style you would like!