Bosch Double Iridium Spark Plugs feature both an iridium firing pin and an iridium ground electrode inlay that offer higher performance and 4X longer life compared to standard copper spark plugs 360-degree laser welded ultra-fine wire iridium firing pin provides better ignitability - reducing voltage requirements up to 24% - and enhanced durability Nickel-plated rolled threads provide superior resistance to corrosion and do not require anti-seize - making installation quick and easy Bosch Double Iridium spark plugs are pre-gapped at the factory and ready to install right out of the box - gap adjustment prior to installation not required Meets or exceeds manufacturer design requirements for OE fit, form, and function for modern gasoline engines - including Gasoline Direct Injection (GDI) engines Compatible with select vehicles (Note: engine affects fitment - verify specific fitment details with amazon confirmed fit fit checker above): MERCEDES-BENZ: 2013-14 C300, 2012-15 C350, 2013 CL500, 2011-14 CL550, 2011-14 CL63 AMG, 2010-14 CLS350 Compatible with (continued): MERCEDES-BENZ: 2012-17 CLS500, 2012-18 CLS550, 2012-14 CLS63 AMG, 2014-18 CLS63 AMG S, 2012-14 E300, 2012-16 E350, 2013-15 E400, 2012-17 E500, 2012-17 E550, 2012-15 E63 AMG, 2014-16 E63 AMG S, 2013-18 G63 AMG Compatible with (continued): MERCEDES-BENZ: 2013-16 GL450, 2013-14 GL500, 2013-16 GL550, 2013-16 GL63 AMG, 2016-18 GLE350, 2016,2018 GLE500, 2016-18 GLE550, 2016-20 GLE63 AMG, 2016-19 GLE63 AMG S, 2012-14 GLK300, 2013-15 GLK350, 2017 GLS500 Compatible with (continued): MERCEDES-BENZ: 2017-19 GLS550, 2017-19 GLS63 AMG, 2017 Maybach S550, 2012-15 ML350, 2012-14 ML500, 2012-14 ML550, 2012-15 ML63 AMG, 2012-13 R350, 2011-13 S350, 2013-17 S500, 2015,2017 S500L, 2012-17 S550 Compatible with (continued): MERCEDES-BENZ: 2011-17 S63 AMG, 2016-17 S63L AMG, 2013-19 SL500, 2013-19 SL550, 2013-19 SL63 AMG, 2012-16 SLK350, 2012-16 SLK55 AMG