Right, measurements on the standard plug for the pre-heater:
Tip: 28.5mm
Shoulder: 4mm
Thread: 11.5mm
(M12x1.25)
Body: 23mm (only part exposed when installed)
Total length: 67mm
Body hex: 12mm
Top nut: 8mm
Dt plug measurements:
Tip: 24mm
Shoulder: 7mm
Thread: 14mm
Body: 27.5mm
Total length: 71.5mm
Protruding plug when installed: 33.5mm
Thread and hex sizes the same as above.
Tip: 28.5mm
Shoulder: 4mm
Thread: 11.5mm
(M12x1.25)
Body: 23mm (only part exposed when installed)
Total length: 67mm
Body hex: 12mm
Top nut: 8mm
Dt plug measurements:
Tip: 24mm
Shoulder: 7mm
Thread: 14mm
Body: 27.5mm
Total length: 71.5mm
Protruding plug when installed: 33.5mm
Thread and hex sizes the same as above.