The sizing on these insoles can be a bit confusing. Superfeet uses a lettering system to avoid having to size their insoles separately for women and men. For example, a size C is equivalent to a women's 6.5–8 and a men's 5.5–7. If your size is on the smaller end of this range, when you get your size C insoles, you just have to trim them a bit to fit your shoes. These pairs have already been trimmed to men's whole sizes. Therefore, a C-7 is cut down to a men's 7, or a women's 8; a C-6 is that same insole trimmed slightly more to a men's 6, or a women's 7. There are also some pairs marked with a number but no letter; that is their size in men's sizes.
There are a few that have only the number size without the letter.