Voltage regulator. VRB-4002D - 4004R, D, 4010A, 4012A, VRP 4001C - 4002D, 4004D, 4006C.
Fits the following:
1939 Plymouth Truck
1939 Studebaker & Studebaker Truck
Contact seller for more information if needed. Quality parts through the years, 40 years experience working with all makes and models of Packard auto. (726)