I hate to be that guy but I’m fairly certain this is a normaphone, not a jazzophone. A jazzophone has two bells, one of which has a built in wah-mute, similar to an echo cornet. They’re such rare instruments that the distinction barely matters but I do think it’s interesting.
This is not a new idea, and were apparently being produced by the DEG company (formed by Donald Getzen) in the 1920's as Jazzophons and normaphons and later in slightly different shapes in the 1980's all imitating the saxophone shape. See ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mQDHYhNkBaA.html