Tremolo Harmonicas- Tremolo harmonicas are Diatonic models constructed with double holes (sometimes 8, 10, 12, or more sets of double holes), each containing two reeds tuned to the same note, one tuned slightly higher than the other. Since both reeds are either blow or draw, when played, both will sound together and the slight difference in tuning creates a vibrating or tremolo effect. The tremolo harmonicas are primarily used for special effects. They are not made to play blues, bend notes, or do anything other than play the most simple melodies. Depending upon the particular model and brand, the major scale would begin on the 3rd or 4th set of holes, and then the pattern would be the same as the diatonic major scale pattern in relation to blows and draws. These harmonicas are not recommended for beginners interested in blues and country playing nor useful for most beginning instructional materials.