The NGK Iridium IX LFR6AIX-11 (6619) Spark Plug is a high-performance plug designed for today’s advanced engines. Built with a 0.6mm laser-welded fine Iridium tip, this spark plug ensures high durability and a consistently stable spark for optimized engine performance.

Key Features

  • Iridium tip for durability
  • Trivalent metal plating
  • Superior anti-corrosion and anti-seizing properties

Features and Specs for Each Model

  • 0.6mm laser-welded fine Iridium tip
  • Thread size: 14mm
  • Thread Pitch: 1.25mm
  • Hex size: 5/8″ (16mm)


  • Long-lasting
  • Efficient fuel consumption
  • Reduced misfires


  • Higher cost than other types

Amazon Customer Review

★★★★★ “I noticed a significant improvement in fuel efficiency and throttle response after switching to these plugs. Highly recommended!” – John D.


The NGK Iridium IX LFR6AIX-11 (6619) Spark Plug offers exceptional longevity and efficient performance. Though it is on the higher end in terms of cost, the benefits it provides justify the investment.