Louet Irish Tension Bobbin HS Fat Core
The fatcore bobbin was designed to make it easier to spin finer yarns, by introducing the same higher ratios as the high speed bobbin, but also adding a thicker center core to simulate a half full bobbin. This helps allow the wheel to not pull in as quickly, assisting in spinning a finer yarn. Its ratios are: 6.5:1, 9.5:1 and 15:1 The fatcore bobbin will fit on all current and discontinued Louet wheels EXCEPT: S40, S45, Victoria, S87, S90.
There is a similair Fatcore bobbin available specifically for the S90 wheel.