Carburetor dashpot this is the early 'short' version, plunger is about 11/16" inches long. Fits all Autolite 2100, 4100, and 4300 carburetors if needed 1967-68 Mercury Cougar and 1961-68 Ford and Mustang. All of these are in used condition, they will have most of the rubber and the spring will be intact. Some of these have a trace of Gold color on them like other carburetor parts. Threaded for installation on factory dashpot bracket, which is 5/16-24. Some, or most carburetors likely had these from the factory, with automatic transmissions.
Definition of the 'Dash Pot' or 'Dashpot': mechanical device which dampens or slows down the throttle plates as they close to the idle position. Not to be confused with the Solenoid which was used with air conditioning among other things.
Ford part number C1AZ-9B549-A.