I bought these to wear in my cycling shoes to add some arch support. They definitely do the job! My 3.5 hour ride yesterday was the most comfortable ride I've done in a while...at least on my feet! I wear a 39.5 in a cycling shoe and bought size C. I did have to trim the insoles a bit, as they were a little too long and wide in the toe box, but I followed the instructions and traced the factory cycling insole on top of the Superfeet insole, then cut to size. I highly recommend these for cyclists who need more arch support.