If your M11/9 machine gun or semi uses the original SWD Cobray factory zytel plastic M11/9 or M10/9 mags, then you need a couple of extra mag loaders.
Regarding what other mags they fit, there are a lot of aftermarket mags for these guns, and we haven't tried most of them. So, we know they fit the factory zytel plastic mags, but but have no way to tell on many of the aftermarket mags. The loaders are brand new right out of the machine gun boxes. Makes loading a mag a fast simple process. Two are show for display, price is each. At this price, stock up now!