This is a great idea.  I think they changed the design a little based on other reviews because I don't have a problem wearing it with any of my nursing bras and mine are 40F.  There is the metal hook and also a small circular stretchy plastic that you can use to attach to your bra so it should work with anything.  I love it.  Most nursing camis have built in shelf bras which never fit right or look good so this is a great alternative because it doesn't have that.  I love layering my clothes so this is a must have.