The 20540 is for 12mm spark plug threads. 12mm Spark Plug Adapter for Compression Tester. 12mm Spark Plug Adapters for 20250 Compression Tester.
Lisle Tools 12mm Adapter For 616-20250
Compression Tester 12mm Spark Plug Adapter for Ford 4.6L 5.4L 6.8L 3-Valve
Compression Tester 12mm Spark Plug Adapter for Ford 4.6L 5.4L 6.8L
Helicoil 5523-12 552312 12mm Spark Plug Thread Repair Kit 12-1.25mm MISSING PART
Ignition Tester Tool for 12mm Spark Plug, Dual Holes
Double End 10mm & 12mm Spark Plug Hole Thread Chaser Restorer Repair Tap
