1. PREMIUM DESIGN: This sturdy adapter is designed to repair damaged threads after using a thread repair tool on spark plug threads. Made with SAE coarse threads, it anchors deeper into the head than metric fine threads, ensuring a secure fit and preventing it from dropping into the cylinder. 2. HIGH RELIABILITY: Professional design to provide you with efficient maintenance solutions. Drill and tap your spark plug hole to 3/4-10, and use your spark plug to screw in this adapter. 3. ENDURING AND STABLE: Made of low carbon steel, this bushing is built to withstand high temperatures and pressures, not easy to deform and damage, ensuring longevity and stability. 4. PRECISE FIT: This tool is an excellent match for 4.6 and 5.4 engine cylinder heads, providing a secure connection for optimal performance. With internal threads of 14mm x 1.25 pitch and external threads of 7/8-9inch. 5. VERSATILE APPLICATION: This repair tool is a dependable solution for fixing damaged threads on spark plug holes and adapters, serving as an important means before replacing the entire cylinder head on engines. Specification: Item Type: Thread Repair Tool Material: Carbon Steel Application: If you have used a thread repair tool to fix the spark plug thread, and blown up the adapter for the spark plug, the adapter is used to repair the thread again. Size: External Threads: 7/8-9inch, Internal Threads: 14mm x 1.25 pitch, Length: 7/8 inch Fitment: for Cylinder Head 4.6 5.4 2 valve engine Package List: 1 x Thread Repair Tool