HKS Super Fire Racing Spark Plug MR Series 50003-MR40XLZ

New series of plugs inherits the best from existing M series and features Ruthenium Alloy Electrode to provide a reliable spark for all vehicles, including vehicles with increased boost or lightly tuned vehicles.

On top of extended lifetime, use of Ruthenium alloy allows a better fuel burn, resulting in quicker throttle response, smoother idle and better cold starts.

Use of this spark plugs on a vehicle not compatible with this type of spark plugs may lead to serious engine damage.

When replacing spark plugs, be sure to compare the shape of a new plug with the installed one.

Please select an appropriate spark plug for your vehicle.

Ruthenium Alloy Center Electrode reduces voltage requirement as well as ignition performance improvement and durability.

Brass Terminal offers film fitting to plug wire or coil-pack.

Plating coating for better insulation and excellent corrosion resistance.

Outer electrode with platinum square chip improves ignition, maximum durability, combustion speed and quality.

The outer electrode has been shortened and engineered with the ideal shape to decrease weight for resistance against vibration.

Indicated price is per plug.