JK Will Sanders model 17 1/2 M Retail price: ¥20,000 SF3 17 1/2M Inner diameter: 17.5mm Throat diameter: 4.3mm U cup Mouthpiece supervised by Will Sanders, professor at the Karlsruhe University of Music and the Maastricht Conservatory. It has been played for about a year, so there are minor scratches. There are no dents on the shank.