Those are reproductions from Charlie Price's Vintage Speed. He owns the "Edmunds Custom" trademark. He has both the short and tall versions of this piece - as well as the 2-5/8" and 2-5/16" air horn variations. I bought mine several years ago. Hopefully the quality of the reproduction remains: Charlie Price Catalog
choose the 'air cleaner' category. These are few page clicks into the list. I think the filter elements are K&N.