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

Stock Heat range:

Brisk Silver Racing spark 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 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.  Brisk Silver Racing RR12S spark plug has 1.5mm optimized diameter fine wire center electrode (not just the tip), which gives more room for insulator between the center electrode and spark plug shell.  More insulation results in a durable spark plug with high dielectric strength - the most important spark plug parameter in forced induction applications.