Needed new magazines for my STI/Marvel conversion. Midway had 10 and 14 round ProMag on sale. I had to remove a little material to let the breach face clear the magazine with a touch of a file.
Magazines have a nice texture, use a coil spring like a Ciener magazine and are easy to take apart and clean.
Put fifty rounds through one without a issue. they eject without issue.
I'm pretty sure this is the same magazine as Kimber conversions use.