The J.A. Custom Special 20 Advanced Harmonica has unique features, including its own serial number. The harmonica features expert reed work, including a distinct embossing method, for a great blues harmonica with a loud but mellow sound. Players will enjoy effortless bends, easy and stable overblows on holes 4, 5, and 6, and an easy and stable overdraw on hole 7. The coverplates and the comb has been reshaped for extra volume and playing comfort.