Niterra 5599 ITR4A15 Laser Iridium Spark Plug

The Niterra 5599 ITR4A15 is a premium Laser Iridium spark plug engineered to deliver exceptional performance, durability, and longevity. Manufactured by Niterra (formerly NGK Spark Plug Co., Ltd.), the world's largest spark plug manufacturer, this plug features advanced laser-welded technology for superior ignition reliability across automotive, marine, and powersports applications.

Key Features:

• Fine-wire iridium-tipped center electrode for optimal spark efficiency and performance
• Platinum-tipped ground electrode provides excellent wear resistance and extended service life
• Laser-welded precision construction reduces excess debris and required voltage to bridge spark gap
• 98% pure copper core ensures superior heat dissipation and conductivity
• Pure alumina silicate ceramic insulator delivers superior strength and heat transfer
• Ribbed suppressor seal prevents spark flashover and misfires
• Built-in resistor eliminates ignition noise interference with electronic systems
• 14mm tapered seat thread with 0.708-inch reach and projected tip design

Performance Benefits:

• Stable idle and smooth engine operation
• Superior anti-fouling characteristics for reliable starts
• Improved fuel efficiency and reduced emissions
• Enhanced throttle response and acceleration
• Extended service intervals compared to standard copper plugs

The ITR4A15 is specified as original equipment on many late-model engines and is cross-referenced as Mercury Marine part numbers 8M0204739 and 8M2018369. The iridium's extreme density (6x that of platinum) and ultra-high melting point make this spark plug ideal for modern high-efficiency engines operating under demanding conditions. NGK Laser Iridium spark plugs are trusted by automotive manufacturers worldwide and deliver OEM-quality performance for automotive, marine, motorcycle, and powersports applications.