Lots of good answers listed. The call in the picture had a dual purpose as both an elk call and a tube call for turkeys. It got it's start as the mouthpiece for an elk call sold by Wayne Carlton, who came up with the design in the late 1980's. There was a long corrugated tube that attached to the bottom to make a bugle call for elk. A mouth call did in fact fit into the mouthpiece. At the time, Perfection Turkey calls made and sold mouth calls to Wayne Carlton who, in turn, sold them under his name as elk calls. The mouth calls could be used on their own as a cow call or inserted into the tube for a bugle call.
Perfection Turkey calls marketed it as a tube call. The beauty of the call is that any of the calls made by Perfection would fit into the mouthpiece giving the hunter many options of how the call could be used. Perfection supplied a single reed call with a thick, heavy latex with the tube that was good for yelping, cutting and kee-kees. Some hunters would put in a three reed mouth call and use it for gobbling purposes. At one point, Perfection packaged the tube call and a trumpet call that they were selling with a VHS instructional tape on how to use the tube call and the trumpet call.
To this day, I still carry one in my vest every spring and have it set up as a gobbling tube.
