B♭ major is a musical key that consists of the notes B♭, C, D, E♭, F, G, and A. It is characterized by having two flats in its key signature, which are B♭ and E♭. This key is often used in various musical genres, including classical, jazz, and pop, providing a warm and rich sound. In terms of scale degrees, the tonic (first note) is B♭, the dominant (fifth note) is F, and the subdominant (fourth note) is E♭. Many instruments, such as the trumpet and saxophone, are commonly tuned to B♭ major, making it a popular choice for ensemble performances.