Horn ID and valve question

[Biggs]

I have acquired what I believe to be a Conn 80A cornet. Below you can see the 'opera glass' tuning mechanism, which I had never seen before. In addition to anything anyone can tell me about this instrument, I have a question about the construction of the valves: why are they so tall and weird? Each piston has a cork section in the top half (see picture), and the springs are little skinny things screwed into the bottom of the valve, which, again, I'd never seen before. Was this a normal thing? Have I been leading a sheltered life of monolithic valve design?