I play a large bore Bach 180-25 and have a need for a free blow. This mouthpiece gives very little resistance due to the large backbore and the open throat. It is deep an gives a good and an even sound throughout the register, the semi-thin rim gives good control. This is not a mouthpiece for someone who squeezes a lot. It does well well in orchestral and chamber settings as well solo-performance where you want a rich sound and a lot of it. Compared to Bach 1B and 1C the cup is a little more V-shaped (a lot actually) and the diameter of the inner rim is slightly less.
A word of warning:
I have tried the mouthpiece in to different Bach trumpets and Selmer trumpet and concluded that the shank is to long for the receivers in these trumpets. I have had a tiny bit cut of on a lathe and this solved the problem. This is the reason I only gave 2 stars for the finnish of the product, everything else about the mouthpice is really nice and well finnished, but when aftermarket modification is a must I don't think they really nailed it.