You are bidding on a used Holley list number 1850 vacuum secondary four barrel carburetor from 1958-61 Ford, Mercury,  or Lincoln V8 engines.   It is NOT to be confused with the later aftermarket carburetor that used the same list number.   The carb is complete, and the throttle plates, adjustment screws, and other linkages move freely. It's got a date code of 915.  As can be seen from the pictures, it's very clean inside.   The carb should be rebuilt before use.   Happy bidding!