How to tell if you have a Small or Large bore Trombone

Easiest, but not 100% accurate:

-If the student is playing on the same trombone which they started with, it will most likely be small bore as most beginners don't start on a large bore trombone

-Generally Large Bore Trombones have an F-Attachment as picture below (left). Small bore (right). 

 

 

-If the Diameter of the bell is 8.5" or larger it is most likely large. 8" or smaller, most likely small. 

Common mouthpieces:

Small:
12c

Large:

5g, 4g, 3g, 2g, 1g, 51D

 

If you are still confused, please don't hesitate to reach out to us through our contact page!