- Key of Bb - 10 hole harmonica - high quality brass reeds - Black with matt finish, Comb: Copper-coloured - Incl. soft case and cleaning cloth The Cascha blues harmonica offers professional quality for a small budget. Its fine appearance and easy handling guarantee lots of fun. The harmonica is not only perfect for ambitious musicians, it‘s also the best choice for beginners. The Bb major diatonic tuning is the most popular type used with blues harmonicas. It‘s a lot more difficult to pl...