Courtois   This model is built in the French tradition, with a bell with gusset and garland, default sheet thickness 0.35 mm. Any other sheet thickness is possible by request. An additional tuning slide allows for tuning in a=435 Hz. The corresponding crook set consists of a C shank as well as crooks in Bb, A, G, F, E, Eb, D, C basso. For Bb basso, a coupler is used with C basso. The crooks' lead pipe is very narrow at the beginning, a mouthpiece with small shank is recommended.