This is a one-piece model. The shank numbers range from 1 to 7, with the shank becoming thinner as the number increases. The "4" shank is slightly thicker than a commercially available 5 shank, providing moderate resistance. By combining it with a 69 backbore, the balance of the playing feel with the instrument is excellent, and I think you can get good resistance. It gave the impression of being very easy to control from low to high notes.