The breast attachment can fit over a size AA-B cup. I am a size D cup, so these are a little small on me. Even so, they rest over the top of my breasts. Four adjustment holes are provided, however, once adjusted (which can take a little time) I recommend not changing the adjustment as the prongs fit very, very, snugly in the holes and constant rearrangement will cause the material to degrade.
The cups themselves are about four inches long and over an inch wide. The electro stimulation area is just under this size, but covers the majority of the area. Each cup has two soft prong openings for the electrical cord. The cord contains four prongs (two for each cup) and is about two and a half feet long.