I have a 37" ribcage, but a "barely B" cup size, and wear these in a Medium.  I originally bought these bras during radiation treatment for breast cancer, because I was forbidden to wear underwires.  But, since I have always needed a bit of extra help enhancing my bustline, I didn't have a single bra without wires.  These bras are super comfortable, very flattering, do not show under clothes, and have a nice, skinny strap that does not look like a sports bra.  I wear them as my everyday bra.  They also hold up well.  I hope they never get discontinued!