Ignitionability, durability, anti-insulation are all reinforced. HKS has made the best plug for both tuning engines and stock engines.

CODE 50003-M35i :
PLUG TYPE : ISO TYPE
THREAD SIZE : φ14×19mm
WRENCH SIZE : 16mm
HEAT RANGE : EQUIVALENT TO NGK #7

CODE 500003-M40i :
PLUG TYPE : ISO TYPE
THREAD SIZE : φ14×19mm
WRENCH SIZE : 16mm
HEAT RANGE : EQUIVALENT TO NGK #8

APPLICATION : (https://www.hks-power.co.jp/en/product/plug/index.html)
Toyota
Nissan
Honda

- 0.6mm Iridium Alloy Center Electrode
- Outer Electrode with Platinum Chip
- Short Type Outer Electrode (Anti-Vibration)
- Thermal Edge
- Spark Support Gap

Performance and Efficiency
- Increased Ignition Performance
- Improved Durability
- Decreased Carbon Deposits