Universal fit for most cars, gasoline engines, generators, diesel engines and other machines. Material and build - Made of stainless steel, strong and sturdy for reliable use. - Design supports smooth operation and improved performance; attractive, durable construction. What it does and why you need it - Restores damaged spark plug threads to enable safe, secure installation. - Compatible with a range of thread sizes and engines, helping you complete repairs without replacing components. Key attributes - Function: spark plug thread repair with inserts and taps. - Compatibility: suitable for cars, gasoline engines, generators, diesel engines and other machines. - Size: uses standard taps and inserts; installation via 5/16" square drive tooling when applicable. - Material: stainless steel for durability and longevity. - Performance: designed to improve engine operation and repair reliability. How to use (installation guide) 1. Match the intended thread repair kit to the repair task. 2. Check the size on the tap and inserts. 3. Drill out the damaged bore or thread to restore the desired thread. 4. Clean the hole with a 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 with 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. Use scenarios - In a passenger car engine, repair stripped spark plug threads to restore proper sealing and torque. - In a generator or small diesel engine, fix damaged spark plug threads to maintain reliability and prevent leaks. - During field maintenance or shop repairs, quickly restore threads on various machines that use spark plugs.