Piano Keyboard: Flats
From any long key, the next key to the left (sounding lower)—whether a long key or a short key—is a flat. The key immediately to the left of B is B-flat. The key immediately to the left of F is F-flat.
From any long key, the next key to the left (sounding lower)—whether a long key or a short key—is a flat. The key immediately to the left of B is B-flat. The key immediately to the left of F is F-flat.