The earliest Ferraris used a simple hand former aluminum scoop. The later 166s had a cast aluminum “Ram’s horn” assembly with a louvered aluminum can at each end. This assembly was made by the Weber carburetor company in Bologna. Most of the aluminum castings have a small tag riveted to the top surface at the center. Some did not. The very early street cars used only a single carburetor but this configuration was soon changed to the more familiar three carburetor set-up. Early Weber “Ram’s horn” air cleaner tag.
The next generation of tags was crescent shaped with a blue field and black writing. These were introduced in the mid-1950s and were used on both the individual coffee can type filters and the new “Three-in-One” type air cleaners which had a single long housing that contained all three individual filter elements. These tags had a chord length between the rivets of 51mm. Early F.I.S.P.A blue and black crescent shaped tags with the 51mm chord length.