Additional information regarding EMP Phasers and EMP weapons can be found HERE.
The EMP Phaser is an electro-magnetic pulse weapon designed by the U.S. military in 2009. The EMP phaser was created for the purpose of eradicating spirits. Because they generate electro-magnetic pulses, they are also capable of destroying electronics and disabling vehicles.
The phaser consists of an EMP generator located in the slide of the gun, the barrel, which directs the pulses blast wave and the battery pack which is located where the magazine is attached. The battery is interchangeable like any gun magazine. The EMP phaser gives out a 'grade one' burst of EMP energy which is enough to cause injury to a spirit. A dozen or so shots eradicate or "kill" the spirit, dissipating it into random energy particles that just burn out.
The rifle phaser consists of an EMP generator in the body of the gun, much larger than the pistol version and like the pistol version, the magazine is a battery pack. Rifle phasers give out 'grade three' bursts of EMP energy which is enough to eradicate a spirit in one to two shots.