Ratios: 6.5:1, 9.5:1 and 15:1. Specify wheel number when ordering. Does not fit Victoria or Julia. This high speed bobbin is clear lacquered to match the finish of the S10, S10DT and S51, S51DT. This bobbin has been carefully crafted to make spinning at high speeds a breeze. The bobbin has a sheave with three settings on one end to obtain three different spinning speeds. The ratios are: 6.5:1, 9.5:1 and 15:1. The high speed bobbin will fit on all current and discontinued Louet wheels EXCEPT: S40, S45, Victoria, S87, S90.