2PCS Spark Plug Thread Chaser Tool, Spark Plug Tapper, High Carbon Steel Insert Tap Repair Set, Double-Ended Spark Plug Chaser Tool with M10 x 1.0/M12 x 1.25 M14 x 1.5/M18 x 1.5 (Type A+B). 【Easy to Use】: First of all, you must apply grease before use, then turn the wrench until you feel more resistance then turn it 1/4 turn counterclockwise/until you feel a slight sound, then choose the right length of the screw sleeve, screw it into the sleeve with a new spark plug, and finally install the screw sleeve into the spark plug hole and that's it.
