1.Fitting: UNIVERSAL: The Spark Plug Thread Repair Tools Kit are suitable for most car, gasoline engines, generators, diesel engines and other machines. 2.Benefit: PRODUCT INFORMATION: The spark plug thread repair tools Kit are made of stainless steel, which is strong, and sturdy. 3.Features: DESIGN: Designed to make the car work well and improve work performance. The design is beautiful and elegant. 4.Useful: INSTALLATION GUIDE:1. Match the intended thread repair kit; 2. Check the size on the tap and Inserts; 3. Drill out the damaged bore or thread for the thread you are intended to restore; 4. Clean the hole with cleaning cloth; 5. Slightly run the tap into the hole, from the bottom tapered cutting edge, to the correct depth by hand or on a machine tool of 5/16' square drive; 6. Clean the thread; 7. Check the size of inserts, then screw in the threaded repair insert using the insertion tool.