In the Halo 2 and Halo 3 Campaigns, it is possible to give powerful weapons to NPC allies. This is an excellent tactic because such allies never run out of ammo—they can fire the weapon limitlessly, and if you take the weapon back, it will have just as much ammo as it did when you traded it. Allies also do not need to reload weapons, this is a huge advantage when an NPC has a rocket launcher, thus reducing the time between shots. The technique is often used with powerful weapons, including the Rocket launcher, Sniper Rifle, Beam Rifle, Fuel Rod Gun, and Spartan Laser.