NGK Iridium IX plugs offer extreme ignitability and exceptional anti-fouling. Tapered cut ground electrode provides improved starting, idling and throttle response. The Iridium fine wire center electrode's durability is six times harder than platinum. Iridium alloy's extremely high melting point is perfect for today's engines.

NGK Iridium IX plugs offer extreme ignitability and exceptional anti-fouling. Tapered cut ground electrode provides improved starting, idling and throttle response. The Iridium fine wire center electrode's durability is six times harder than platinum. Iridium alloy's extremely high melting point is perfect for today's engines.

NGK Iridium IX spark plugs feature an ultra-fine center electrode that's designed just thick enough to ensure the maximum durability and life of the spark plugs—and just thin enough to create an accurate and consistent spark.

Buy NGK 6637 Iridium IX Spark Plug (4 Pack) Fits select: 1986-1989 NISSAN D21, 1985-1986 NISSAN 720 at Walmart.com

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NGK's Single Iridium Series Plugs were Designed Specifically for the Performance Enthusiast. Fine Wire Center Electrode Ensures High Durability and a Consistently Stable Spark; Iridium Alloy has an Extremely High Melting Point, Perfect for Today's High-Tech, High Performance Engines