You are buying 2x BP5FS NGK SPARK PLUG FIT Ford LTD FC 4.0L 6Cyl Iron Head Gap mm:0.8. 79-82. The workhorse, at the heart of smooth-running engines around the world. Spark plugs are the "window" into your engine (your only eyewitness to the combustion chamber), and can be used as a valuable diagnostic tool.