This is a new old stock Bridgeport brand thermostat #4 that opens at approximately 142-150 degrees.  This fits the following; Hudson 1939-1942 (except Super and 8 Cylinder); also fits Hudson 6 cylinder 1946-1947; Nash and Lafayette 1934-1952 all; Studebaker 1937-1952 all (except Champion) and also fits 1933 Plymouth.   Part is new never used and in excellent condition.   2 1/2" diameter and a high profile of 2 1/2" so make certain that it will fit your housing before buying.