This harmonica has a one octave lower range than the Soprano Single. Play this harmonica together with a bass harmonica for a deep, vibrant low-end sound. The Alto Single contains 37 holes with a range of C (one octave lower than middle C) through C3 in the key of C- three fully chromatic octaves. The holes are arranged like the keys on a piano - the 'white' keys on the bottom row and the 'black' holes on the top row. It's solid brass reed plates hold the ultra precise phosphor bronze reed system, tuned by laser. The select hardwood body and super smooth, solid brass, ergonomic reed covers create unparalleled playing comfort. The AS-37 comes in a leather covered, wooden case that is velvet lined. This is a large harmonica - about 13 inches long, 2.25 inches wide, and 2 inches tall. The mouthpeice is about 3/4 inches tall.