Bell Diameter is 22”, a .729 bore, and 4 piston valves.
On the bell, it says: “MADE BY / C.G. CONN LTD. / ELKHART, IND.” on bell.
IMG_3087 by [url=https://www.flickr.com/photos/129235491@N05/]https://simonettitubacollection.com/ins ... helicon-4/
IMG_3087 by [url=https://www.flickr.com/photos/129235491@N05/]