We have discussed in other descriptions on this site about Conn's thorough and constant experimentation. Here's an example in the flesh! This is a 1932 vintage prototype from the C.G. Conn factory. Oddly it is has a serial number of 254920, even though it was never intended for public purchase and was purely a test subject. Makes you wonder how many other experimental horns were lost at the Conn factory over the years! In any case, this is an extremely early example of what was to become the 10M. Though it lacks the famous "Naked Lady" engraving, it does feature same side bell keys, which were a staple of the transitional model altos but not yet seen on the tenors.