Conn 40B Connqueror in C & Bb
Date: 1935. Picture used with permission by the owner.
This is probably not an experimental model but a custom order: a 40B with interchangeable slides for C and Bb. It appears to have been built in C: the valve slides are marked "Bb" so the player can tell how far to pull the slides out to play in Bb. The leadpipe is also a little shorter. The bell is engraved "Casa Luna Zaragoza" suggesting it may have been produced for someone in Spain.