Fox C Bocals are our basic student bocal. They are the bocals provided with the Renard models 51, 41 and 222. The C bocals are of nickle plated brass and are available in lengths 0 through 4, with 0 being the shortest. Lengths 1, 2 and 3 should be considered the "normal" lengths. If you do not know what length you need the #2 is probably your best place to start. In general, the extreme lengths 0 and 4 should be avoided without a good justification. Hickey's recommends the Fox C bocals as an excellent replacement bocal for school use and with most makes of bassoons.
Fox Bocals run 1 size smaller than Heckel and most other bocals. So a Fox 3 would be equivalant to a Heckel 2.