The J.A. Custom Super 64X Master has excellent response and tone. Out-of-the-box chromatics are well known to have response issues in the top octave, but on the Master model all holes and reeds are fully playable with equal response. The 2 part slide mechanism, gives the harmonica a much better slide action, but it also give the player better response and dynamics. The valves are modified for a much smoother action. It is assembled with screws for easy maintenance. Are you looking for a harmonica with incredible volume, perfect response and a smooth slide action, then you do not have to look any further!