I believe they are. I did not use these myself. They were given to me and I don't have anything to compare to or a box, but they are bigger around than a normal bottle and the nipples are more like a Playtex nurser only not flattened on the top.
I looked at the nipples and it appears the smaller bottles have a slower flow nipple than the larger ones. The holes are bigger on the larger bottles and almost closed on the smaller bottles.