A good magazine, starts out with some weird kinks but ends up being much more useful than the HFC M190, as it hasn't broken on me yet. Basically, it started out not fitting in my M9, so I had to take off the bottom portion of the mag(the part you normally take off to put in the CO2), but that wasn't really a problem. I had to put in the magazine several times, cock the gun back, put the mag in, and for some reason it just stuck perfectly. Before that, it had kept falling out for no reason. These are the "kinks", which in the end proved to be absolutely no problem. It took me about ten minutes to get the mag fitting perfectly in the gun, and no modification was necessary, really. I eventually replaced the side grips with wood side grips, and now I can put the mag in with the bottom portion perfectly. This is really all because of the M9 that I had, and may differ completely based on the M9 one owns. Overall a great buy, the most reliable M9 mag I've had, better than the extended magazine from HFC itself (and I was using a HFC M9, too).
My rating: 9.5/10
+Everything an M9 mag should be.
+Simple to open the bottom to put in CO2, although you may need a coin.
-Kinks to work out at first, but after ten minutes you should be fine.
-Side grips may interfere with the bottom of the mag, replace them if this bugs you.
Rating: [5 of 5 Stars!]