The M45HL uses the stock heat range for the BRZ/FR-S and is meant to be an OEM replacement. This 45 heat range that HKS uses translates to a 9 heat range on the NGK spark plug scale or a 27 on the denso spark plug scale.
The Super Fire Racing M-series Iridium Spark Plugs are designed for improved ignition performance, durability, and reliability over stock plugs. The plugs feature a 0.6mm Iridium Alloy Center Electrode that reduces the voltage requirements and improves the durability and performance of the ignition. The outer electrode incorporates a square platinum chip that when combined with the iridium center, also boosts the ignition performance. The thermal edge and spark support gap help prevent carbon buildup on the plug to make the plugs last longer under various combustion conditions. To prevent premature detonation, the use of a nickel coating on the housing is applied to add that extra safety measurement.
Set of four spark plugs.
Fits all 2013-2021 BRZ And Scion FR- S