NGK UR4 Spark Plug Copper Core

The NGK UR4 is a genuine NGK spark plug, available to order. Equivalent plugs from other makers are shown in the alternatives below.A conventional NGK nickel-alloy spark plug with a copper-cored centre electrode. The copper core carries heat away from the firing tip quickly, which lets the plug run cooler under load while still burning off deposits at low speed, so it resists both overheating and fouling better than a plain nickel plug. NGK's standard range is the direct replacement where a conventional plug is specified and remains the sensible choice for classic engines,