NGK CZ256 / 90066 Ceramic Glow Plug Genuine NGK Component (90066 ) As opposed to a metal rod glow plug, the heating coil of a ceramic glow plug has an especially high melting point. It is also sheathed in silicon nitrite, an extremely rugged ceramic material. The combination of the heating coil & ceramic sheath enable higher temperatures & extremely short preheating times due to excellent thermal conductivity. Also, ceramic glow plugs have a more compact design. This is important, because there is very little free space in todays engines.DIMENSIONSHex (mm):12 Thread diameter (mm):M10 Thread pitch (mm):1.25 Overall length (mm):86.5 Heater tube length (mm):20 Terminal (mm):M4 threaded Marked voltage :11 VIf you are unsure as to whether this is the correct part for your vehicle, please don't hesitate to contact us. Alternatively please use the cross reference table above.