ADD-ON KITS ONLY PROVIDE THE NECESSARY TOOLING TO CONVERT TO BIG-SERT You must have the original kit. What is Included: Drill, Tap, Bushing, line pin, Inserts and dowels. Second repair after a failed coil style insert. Kit includes 10 inserts of  the P/n 52155 and Head alignment dowel P/n J-42385-508BS Qty 2