Iridium Long-Life Spark Plug (3421) by Denso®. 1 Piece. Gap: 0.044". O.E. Recommended Iridium Long Life. Patented Iridium Alloy Plug (90% Ir) with Platinum Ground Strap. Denso's patented Iridium alloy is more durable than even Platinum, allowing the center electrode to be shrunk to only 0.7 mm in diameter. This produces a dramatic improvement in ignitability and spark plug life. Denso's Iridium Long Life spark plug is standard equipment with a number of automakers including GM, Toyota, Honda, and Mitsubishi.
- Fine-wire iridium center electrode
- Platinum ground electrode
- 360 degree laser-welded spark tip
- Sustained spark performance over 100,000 miles
- Withstands higher pressures and temperatures
- Reduced spark plug wear and erosion
The Denso Iridium Long Life plug is fast becoming the standard for today's high-tech engines. Properties of Denso's patented Iridium alloy have broken through the spark plug technology barrier. Employing a revolutionary new 360° laser-welding process, Denso has created a spark plug unlike anything on the market today. Designed for durability under the most extreme conditions, Denso's patented Iridium alloy is six times harder and eight times stronger than conventional Platinum and can handle temperatures in excess of 4,000°F.
Denso® factories are QS9000 and ISO9000 certified worldwide, just one of the many reasons why zero defects for parts produced in the millions is a reality for DENSO. A recipient of the prestigious Deming Award for quality in 1961, Denso spent over five decades perfecting technology and processes, a claim that few automotive manufacturers can make. Denso First Time Fit™ products — including A/C compressors, starters, alternators, oxygen sensors, ignition wire sets, fuel pumps, cabin air, oil and air filters, wiper blades and more — are products built and tested to OE-standard offered for the aftermarket by DENSO. Each of these products is precision-built for exact replacement so you don't have to worry about doing the same job twice.