I have a very high instep and so ordered a 2E.  These shoes even though marked a 2E looked very narrow and they do not work well if you have a high instep.  The top stretchy material does have some give to it, but feels very tight across the top of my foot and leaves seam marks along with an indentation of the number 801 on my skin.  Will try to wear the anyway to see if they will stretch out, but if you have a high instep just be wary about this.