Spark plug, R7282, 10.5 with 22 mm

NGK R7282-105 – Iridium "Shorty" Racing Spark Plug (Heat Range 10.5)
Its mandatory to use a washer under the spark plug so it comply with the technical regulation

The NGK R7282‑105 is a high-performance "shorty" spark plug tailored forOKJ - OK - KZ, where engine bay clearance is tight. It features an iridium center electrode, platinum ground electrode, and built-in resistor (~5 kΩ), delivering low ignition voltage, precise spark, and exceptional durability under extreme conditions.
With a mid-range heat rating (10.5), it performs excellently in normal to warm environments, resisting fouling while maintaining combustion stability. 
Specifications:
Thread & Reach: M14 × 1.25 mm, 22 mm reach - Its mandatory to use a washer under the spark plug so it comply with the technical regulation
Heat Range: 10.5 – balanced for warm-weather competition
Electrodes: Iridium fine-wire center and platinum ground — outstanding durability
Resistor: Yes (~5 kΩ) to suppress EMI
Durability: Significant lifespan with stable performance at high RPM