Three pack in common keys, A, C and G. Designed for rich tone and superior musical expression, the Silver Creek Diamondback Harmonica is a 10-hole diatonic instrument that comes in 5 of the most popular keys (A, C, D, E, and G). You can play in nearly every musical genre, on stage or in the studio. The smooth comb and extra-thick reed plate give this hand-assembled instrument solid tone and superior playability. And the contoured cover plate offers outstanding volume and solid resonance throughout the range. Now you can own a pocket-sized, top-quality portable instrument that is ready to play at any time, anywhere.