Original U-Groove Spark Plug (3381) by Denso®, 1 Piece. Gap: 0.044". Resistor Plug with Patented U-Groove Design. Denso's patented U-Groove spark plug enables complete combustion by allowing the spark to fill the gap created by the U shape. The ball of fire created in the U-Groove develops a larger and hotter flash front that virtually eliminates excessive fouling and erratic starts caused by poor fuel mixtures.
- Made in Japan
- Long # K20HR-U11
- 100 percent pre-fired to ensure reliable operation
- Copper core center electrode for superior thermal conductivity
- Unique five-rib insulator reduces flashover
- Patented U-groove ground electrode design fires leaner mixtures than conventional plugs
- Precision machine-rolled threads reduce seizing and cross-threading in delicate aluminum heads
- Wide range of part numbers for thousands of applications, including classic and collector cars
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.