Converts 14mm tool to 7/8-18 threads for broad compatibility
Enables use of standard compression testers on vintage spark plugs
Durable USA-made construction for long-lasting performance
Simple attachment for quick and easy setup
Summarized by Shop
Compression Tester Adapter- Fasten this to a standard 14MM Compression Tester- This adapts the 14MM tool to the 7/8-18 Head Spark Plug Threads- USA made