This recorder is in the key of F, although it has the same fingering as both the treble (alto) and the sopranino. Being one of the largest in the family, it can be difficult to reach some of the holes, so keys are often added to help with the furthest.

We show here two different styles of bass - the knick style such as the YRS302B, which has a normal top joint which is bent slightly for easier reach, and the crook style such as the Aulos 533 which has a slim metal tube with a plastic mouthpiece.