TubeNet

This is a photo from an add on eBay right now. I have never seen a helicon like this. Any ideas on the manufacturer? That crazy tuning slide is just asking to be crunched.

My guess would be that the tuning slide was an add-on to lower the pitch.

Henry Distin, Williamsport Medium BBb Helicon in High Pitch, with Low Pitch slide added for A=440

Just a casual opinion.

I would say Distin or early Keefer. I have owned Distin helicons and Keefer sousaphones with similar main tuning slides. I tend to believe that it is a Distin though because the rest of the valve tubing looks like the earlier configurations that I have seen or owned. On the later versions they curved the end of the tuning slide to follow the curve of the body, undoubtedly for the issue you mentioned.

Keefer Eb Sousa. Wrong key, wrong bell, but notice similarities...