Pictures after the cut. They include comparisons with the large Fleurcup, since I have one of those already. The Natural Mamma only comes in one size.
In this picture, you can see that the Natural Mamma cup is made of a milky, semi-translucent silicone. Hopefully you can see the three grip rings on the body of the cup. They are less prominent than the Fleurcup's grips and are full circles all the way around. The line closer to the rim of the cup is where it bumps out and the silicone gets thicker. From that line to the rim is possibly slightly stiffer. The stem is flat and ovalish shaped with two grip lines on it. The overall shape is very elegant, I think!
Here, you can see how the Natural Mamma is similar to and different from the Fleurcup; it's like a stretched out version of the Fleurcup. The Natural Mamma is longer and maybe a tad more rounded at the base and is just slightly less stiff than my Fleurcup, which is an older version (I think the older ones are supposed to be stiffer than the newer Fleurcup?). The opening is not as flared as the Fleurcup's. Another difference is the four holes in the Natural Mamma go straight through; they are not angled like the Fleurcup's. I would say that the rims are about equally prominent.
While the Natural Mamma is longer, it is less wide. When I filled the Natural Mamma to the rim with water and then poured the water into the Fleurcup, it was well above the holes and still just about full. There is a very slight difference in capacity, and I don't think it would make much practical difference. The Fleurcup has a totally smooth inside. The Natural Mamma is smooth on the inside except for two short, horizontal lines going down the side under one of the holes.
The Natural Mamma comes in a stretchy neoprene pouch with a zipper. Both the Fleurcup and Natural Mamma are in my pouch, both also in muslin pouches I got from Feminine Wear. At least two more cups could fit in there, so it is very roomy. It's the only packaging that it comes in - you get the cup inside the pouch (with an information sheet) inside the mailing envelope. No plastic or boxes.
Hope this helps someone! If anyone wants other information or to see different photos, feel free to ask!