The Maglula Loader/Unloader is simple to use in either loading or unloading mode. The loader/unloader eliminates thumb pain, wear on feed lips, and prolongs magazine life. It is crafted from durable reinforced polymer, lightweight, and is reliable in all weather. This model is compatible with Sig MPX 9mm polymer magazines. Find other magazine loaders like this one for the best price at GrabAGun.