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.
The third type of air cleaners was the more conventional “Coffee Can” model. They used a satin black painted steel top and bottom with side panels made of louvered aluminum or perforated and nickel-plated steel. The earliest ones had the Weber information embossed in the top but this was soon replaced with a smooth top using the same Weber tag riveted to the top. Early “Coffee Can” top Weber tag.