2 packs of 6! 10mm x 1. 1/2" reach (~13mm) These are NOS heli coil inserts for repairing stripped plug threads. Made in USA. These are inserts only, you'll need a heli coil tap and install tool. R13
12x Helicoil 14mm Spark Plug Thread Repair Inserts #R513 14- 1.25mm Reach 7/16"
12x Helicoil 14mm Spark Plug Thread Repair Inserts #R512 14- 1.25mm 3/8" Reach
Helicoil 10MM 1.5 INSERTS P/N R1084-10-N (Pack of 12)
Owatonna Tool Co. OTC 14mm 10mm Spark Plug Hole Thread Chaser M-1014 VTG USA
Lisle 20530 10mm Spark Plug Adapter for Compression Tester
Lisle 20530 10Mm Spark Plug Adapter