Interesting... I found a link on their
FB page where they were promoting
"Pre-order 2 MPX mags and get 3 free AR mags". When you click, it takes you to your cart with 3 of each in there. I changed the amount to 2 MPX mags and it still shows the 3 AR mags free.
Looking at a review for their PSA U9 mag review, it states
"The new PSA U9 mag is an extremely durable magazine with several awesome features. It is constructed with the THRiL polymer-matrix (PMX) material for extremely high durability and performance. This PMX technology provides exceptional impact resistance. The magazine also contains stainless steel feed lips and an elastomeric strike plate to help improve performance from many other magazine options. It is very easy to load and cycles rounds through very efficiently and smoothly. This 9mm magazine is also bigger than many others you might already own and can hold up to 35 rounds, offering a new viewpoint in the debate between 20 and 30 round magazines."
I would think the MPX mags would be of the same construction.
The reviews for their other mags seem solid. I decided to pre-order 4 for the range and got 6 free AR mags. $39.95 apiece, 35 round capacity, free shipping, no tax...just have to wait for March 31st.