on the left is the 30 round insert. attached to the spring (and shown again on the right) is the 50 round setup. the FN part looks just like the part in the picture, only it is the same material as the mag.
You can also modify the 30 round plate easily yourself. Just cut away everything leaving just a baseplate with the nub that locks it in place. I did it with a jigsaw in a minute. A dremel could do the same thing easily. And if you do end up breaking it, you can always still buy the 50 round plate.
Maryland has a law prohibiting conversion to mags over 20 rounds or buying mags in state over 20 rounds.
You are legally allowed to own then though if brought into the state.
I took mine out of state and converted them then brought them back in state. :?