This is a home made slide trumpet, measuring about 2 ft long when contracted. It was meant to be tuned to B flat, but it wound up being tuned to C. I made this in high school as a side project, so the construction is sturdy, but unsightly. That said, it looks pretty neat.

Yes it does work, though it does not sound that good. I played trumpet for over a decade so I can make it dance, but it sounds tired. If I had a bell mandrel, I would made another. With five years of machine shop training since making this, I think I could make something that would be nice to listen to.