Lovely vintage Vincent Bach 2.5 C trumpet mouthpiece from the early 1960's ( not dots).Condition is good but as you can see it has been played a lot. Clear insertion marks and slight loss of silver plate. 
It sounds great and is a useful size for Bb, C and Eb/D trumpets. Full rich sound which easily brightens when you want.
It has a slightly flat rim but there is decent bite. 
From Bach web 
"It is a trumpet mouthpiece with a medium cup, a 16.5mm to 16.51mm cup diameter, and a medium-wide rim, designed with a "brilliant, crisp" tone."
I am selling as I prefer Schilke MP with my Schilke trumpets.
I'm sure this is the right MP for someone. Also "collectable"