I tried out an insight X2 light for my M&P Compact 9 but found it to be moving loose forward and backward. It seemed to only clip on to the rail so I don't really know if it's something I want to trust being so loose although I'm pretty sure it won't come actually come off. Is there any other sub-compact light that can be used on the M&P-C that would be similar in use to the X2 but fit tightly?