Otherwise gauge will not work
and some models require the RPM on bottom
Gauges have a 6 or 12 V bulb & holder included so owner has option to use or not to use All three gauges fit in a dash opening of 2" / 52mm
Has 5/8" - 18 UF capillary probe end and 1/2" NPT bushing
Tachometer for Massey Ferguson Tractor 20D 230 231 240 550 1674638M92 187718M92 Otherwise gauge will not workTachometer fits Massey Ferguson: 20D, 20E, 20F, 30E, 30H, 40E, MF 50, MF230, MF231, MF240, MF550, 230, 231, 240, 250, 255, 298, 550 UK Replaces Massey part numbers: 1674638M92, 187718M92, 1674638M91 Fits 3 3 8" 85mm diameter, 5 8" 18 UNF Thread, Anti Clockwise Rotation, This tachometer has chrome bezel with glass lens and are Yellow Zinc "Cad" Plated for corrosion resistance protection! They have mounting studs and brackets, rubber gasket seals for