M12 x 1.25. This kit is not for spark plug repairs. KIT CONTAINS: Drill, Counterbore, Tap, Installation Driver. 5 Steel Inserts - 12MM X 1.25 15.0MM LENGTH INCLUDED. Then screw the insert onto the prepared hole.
PERMA-THREAD M12 X 1.25 Spark Plug Thread Kit Set - No. 1212-413
6483 5Pc Wheel Hanger Set M12 x 1.25 (wheel stud version), M12 x 1.5, M14 x 1.25
Tap & Die Set 4 Wheel Studs & Nuts Thread Re-Cutting M12 x1.25 M12 x 1.5 M14 Kit
M12 x 1.25 Metric Thread Repair Install Tool Insert Kit M12 Helicoil Coil 15pc
Combo Thread Chaser Tool M8 x 1.25, M10 x 1.25, M11 x 1.25, M12 x 1.25 Set of 4