The Plug-A-Long does just what it's name implies... it allows you to take aircraft plugs that you have removed along with you, without getting them mixed up or out of order. In fact, each hole is labeled to insure that each plug goes back in the exact place it came out of. Sturdy steel construction.Holds 12 spark plugs each hole stamped with cylinder number also marked top and bottom so each plug can be identified easily, no mix-ups. Plugs can ve serviced and returned back to where they were removed from. A must for aircraft mechanics. Made from 18 gauge steel. Blue powder coat finish.