This high speed set for the S10C and Victoria (beech) contains a high speed flyer, 3 bobbins, a small whorl (added to the existing whorl) and a hook for threading the yarn through the orifice and the flyer hole.

The orifice is less than a quarter inch, but you can take out the inserts and have a 1/3" or 1/2" orifice.

Ratios are 1:20 and 1:30.