TromboneChat

What mouthpiece does Elliot mason play on?

Giddings and Webster I believe

Yes, now called Giddings. I have an unmarked prototype of Elliot's mouthpiece (verified by Ian Giddings).
Cup I.D. ~24.5mm / 0.96"; throat 5.87mm / 0.231". Quite small - a bit like an enhanced 12C. Nice shape though.
Too small for my face, so I've set it aside. Make me an offer!

He does play a Giddings. I ordered one originally when they first came out. Mine was a Stainless Steel Version. Elliot plays the titanium one. If I’m not mistaken the production version wasn’t quite the same and they stopped making them. Only a small batch was made and sold. My buddy still has piece that I sold him if you’re looking at getting your hands on one. He might be willing to sell it. It’s about a 7C size. Maybe a touch larger (closer 6 3/4C).

I too had one of the original ones in steel, I'd agree with Luke on the size.
It had a great sound however there was something going on with the rim, like it hadn't been rounded off properly and therefore had quite a square/flat high point which just made it feel weird ..... Hence I sold it on. I believe Elliot has been through a few iterations before arriving at the one he's currently on. He has an allergy to brass/silverplate.