NGK CZ51 / 3209 Ceramic Glow Plug Genuine NGK Component ( 3209 )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 and ceramic sheath enable higher temperatures and 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):12Thread diameter (mm):M10Thread pitch (mm):1.25Overall length (mm):84.5Heater tube length (mm):22Terminal (mm):M4 threadedMarked voltage :6.5 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.