The natural harmonic series of the bass trumpet ranges from the easily playable 1st natural (fundamental) to the 10th natural. Since the interval of one octave between the 1st and 2nd naturals cannot be fully bridged even with the use of valves, there is a gap of one tritone (an augmented fourth). The fingering is the same as on the C trumpet.
The low register of the bass trumpet in Bb also includes the pedals from E1–Bb1. In theory the upper register can extend as far as F5, but these high notes are practically never used and sound much better on a normal trumpet.
Unlike the C trumpet, the naturals 11 and 12 are extremely difficult to produce and are consequently not used.