[rotorwrench]

The model A horns made by EA Labs, Stewart Warner, Ames, GIM, and Sparton. Each manufacture had their own way to identify their products. I think Sparton was the only one to have a tag but one of the others may have but in a different location. The others stamped their ID in varying places on the cover, horn projector, or motor body. There were different ways to adjust them and some had holes in the cover for that and positions of the holes also vary. Not all companies manufactured them during the whole of model A production. The Sparton horns are likely the most common next to SW but some of them may have mixed and matched parts if they are original at all.