Our heavy duty replacement 4 terminal Voltage Regulator fits these model Tractors:  D21, 160 through 190XT, 200-220 Gas or Diesel engines. Always inspect the VR plug! Corrosion in the terminals and connector can cause a lot of charging issues. If the plug looks questionable, change it out! Our VR Pigtail connector P/N 1514A-17 fits the bill and can be changed out in minutes! This is a light weight solid state Voltage Regulator made in the good old US of A!