The Gr Technologies Standard 3 Backbores

#1 - This backbore produces a focused core of sound and  outstanding intonation and projection.  Ideal for lead trumpet work and commercial settings.

#2 - This backbore features a fat sound with some edge and medium blow resistance.  An ideal backbore for all around playing.

#3 - Low blow resistance with a clear centered, yet full sound.  Ideal for everything from jazz to symphonic work.