Voltage regulator for Military gasoline powered generator sets, MEP-016A / MEP-017A / MEP-018A, etc.
P/N 13219E0883. NSN 6110007647621. Made in USA. Factory new/unused. Fits various models ranging in size from 3 KW, 5 KW, and 10 KW.
Also included but not pictured is the voltage adjust rheostat, part number M22/03-00191FD.