NGK 95399 Spark Plug

NGK Laser Iridium Spark Plug 95399

NGK 95399 is a Laser Iridium High Ignitability spark plug built for precise ignition performance and stable combustion. It uses an iridium center electrode, a square platinum high-ignitability ground electrode tip, and a 0.036 in pre-gap to support consistent spark delivery in demanding engine conditions.

Key Features

• Laser Iridium High Ignitability design for focused spark performance
• Iridium center electrode tip material for durability and ignition consistency
• Square platinum ground electrode tip design for high ignitability
• Copper center electrode core and nickel ground electrode core
• 5000 ohm resistance for ignition system compatibility
• 10 mm thread diameter, 14 mm hex size, flat seat, and 26.5 mm reach
• NGK part number 95399, also listed as SILMAR9B9

Detailed Description

As part of NGK’s Laser Iridium High Ignitability line, this spark plug is engineered with a fine iridium firing tip and a platinum-enhanced ground electrode profile to promote reliable ignition response. NGK’s long OE supply history and broad coverage across domestic and import vehicles make this a practical choice for drivers and technicians looking for an OE-style replacement spark plug. The 95399 spark plug is a direct NGK reference for applications that call for SILMAR9B9, and it is commonly searched as NGK 95399 spark plug for Honda Civic and other vehicle-specific ignition service needs.

This part cross-references NGK 95399 and SILMAR9B9 for the same application.

What It Helps Address

• Rough idle caused by worn spark plug electrodes
• Hard starting from weak or inconsistent spark output
• Misfire conditions related to ignition wear
• Reduced throttle response from degraded combustion efficiency
• Maintenance replacement for vehicles requiring a 10 mm, flat-seat iridium plug

Installation Notes and Tips

Verify the required thread diameter, reach, seat type, heat range, and terminal style before installation. The pre-gap is listed at 0.036 in, but final gap should always be checked against the vehicle service specification. Use proper torque procedures and inspect ignition coils, boots, and wiring during spark plug service. For fitment-based searches, this NGK 95399 spark plug is commonly referenced for Honda Civic ignition maintenance where the engine specification matches the listed dimensions.

Quality Assurance

NGK is a major OE spark plug supplier with extensive North American manufacturing, inventory, and distribution support. The brand’s OE background and application coverage are reflected in the design and specification control behind part number 95399.