BRISK Silver Racing RR12S Spark Plug 14mm thread, 25mm reach, 5/8'(16mm) hex, tapered seat, non-projected tip, resistor, fine wire 1.5mm Silver center el., Cut-back ground electrode Popular application:Compatible with the following vehichle types, 2011 FORD Mustang 5.0 2011 Chevy Camaro V6 GEN 3 HEMI Engines 5.7L, 6.1L Dodge SRT 4, SRT 8, HEMI, 300 and more. ION, PT Cruiser, Ford Focus..... Brisk Spark plugs for the new 2011 FORD 5.0L, V8 engine are: Stock Heat range: ROR15LGS, RR15YC-1 One step colder: ROR14LGS (N/A app. only), RR14YS (projected tip- low boost forced induction app.), RR14S (non-projected tip-good for nitrous or forced induction) Two step colder: RR12S (non-projected tip) – High Compression, Forced Induction and/or Nitrous Three step colder: RR10S (non-projected tip) - High Compression, Forced Induction and/or Nitrous. Brisk Silver Racing plugs have a better ignitability than conventional performance spark plugs, and offer better performance and reliability in high boost, nitrous or high compression applications. Silver is an element with the most free electrons, and is the best electrical and thermal (heat) conductor of all metals! Better than gold, copper ...and many times better than Iridium. The Brisk Silver Racing plugs have a fine wire center electrode (not just the tip), which gives more room for insulator between the center electrode and spark plug shell.