The "C" is for machines that that have rotary hook systems and a maximum stitch width of 9mm, which a 220 does not have. The manual does state that the "C" foot is usually larger to fit the wider feed dog of the rotary hook machines. I have a 230 PE and have "C" presser feet, they work okay, but I would think that the feet without the "C" may cost less. Don't really know for sure.