Swan's tremolo harmonicas are double reed instruments. The bottom row of holes features the same notes as the top row, tuned slightly higher. This special tuning creates the tremolo's distinct sound, a beautiful vibrato effect with a richer tone. These harmonicas are primarily used in ballads, folk, reggae & gospel music. 's tremolo harmonicas are double reed instruments. The bottom row of holes features the same notes as the top row, tuned slightly higher. This special tuning creates the tremolo's distinct sound, a beautiful vibrato effect with a richer tone. These harmonicas are primarily used in ballads, folk, reggae & gospel music.Special note: multi-chromatic harmonica end of a putter than ordinary harmonica, we call it change the sound bar, met scores in semitones when playing as long as the putter went to press. (Press into the equivalent of the black keys on a piano) playing without special skills to master, just gently by hand can blow a semitone. Chromatic 10 Hole 10 Tone (two full octaves)