The RT1 Lead Trumpet Backbore was inspired by the West Coast “studio” sound. It is small internally. If you are able to play a Schilke AA or A backbore or a Reeves 692SL, you’ll love this one as it provides a firm, even resistance across all registers. The bore is #27 at the interface and #30 at the apex. As you overcome the resistance of the RT1 the payoff is in efficiency and projection. Its intense focus makes it ideal for studio recording and miked live performances.