What is this piston from?

[arpthark]

I have a spare piston. What is it? Reynolds? Bore is about .68x-something verging onto .69x with my crappy calipers.

[LeMark]

I'm going to say conn, but the button is different. The valve cap itself looks identical to my 1903 Eb I had

[bloke]

The finger button is absolutely Reynolds but the rest of it doesn't look like anything I'm familiar with made in the United States

[York-aholic]

As Bloke said, finger button is Reynolds. The rest may be Frankenpiston (ie I have no idea).

[gocsick]

Looks a lot like the ones on my Holton Collegiate Sousaphone. I can do a better comparison when I am home tonight.

Here's one in reverb... but it is hard to zoom in.
https://reverb.com/item/37249961-holton ... phone-1957

Edit: Here is mine... The bore is a match and so are the looks. The 1 and 2 finger buttons are original.. I lost 3 at a gig and that was just one I found to fit

[bloke]

That makes sense because Holton and Reynolds are both SAE 8-32. I've never had a Collegiate in the shop - only a top line Holton, so I wasn't able to recognize those caps. There are European instruments with caps that look very similar.

By the way, my name is not From.