Denso - K20HR-U11 - 3381 - U-Groove - Subaru - Sport Compact - Spark Plugs
Spark plugs are not all alike. With the world-famous DENSO U-Groove spark plug it's easy to see, thanks to its patented U-shaped ground electrode. The U-Groove forms a channel for the spark nucleus to form at the instant of ignition, limiting quenching to generate a more potent spark. The premium features don't stop there: DENSO's distinctive five-rib insulator in purified alumina prevents leakage and flashover, while dual internal copper-glass seals and a copper-core center electrode with nickel-alloy tip assure reliable spark delivery. To keep your engine running smoothly, its spark plugs must fire 25 times a second or more. If just one spark plug skips a beat you'll know it instantly, with rough running, poor acceleration, and reduced fuel economy. DENSO U-groove spark plugs combine dependable performance and superior value.
WRX Fitment: 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014
STI Fitment: 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015