The Stinger P311, also known as the "Mean Green" is a handgun found in the MECU. It is a clear pistol with a green grip. While it is based off the airsoft pistol by Crossfire, it acts as a real gun in the canon.
The P311 is shown to be very accurate and powerful, usually able to take down opponents in one shot. It also has a high magazine capacity as it very rarely needs to reload. It is one of the few weapons shown on screen that can actually be reloaded instead of the actors just using gestures that simulate the act of reloading.
It is currently unknown who manufactures these weapons, but they are very commonly used by street gangsters as Jack uses one.