Abstract : The TASER is a device that propels two darts into a subject and transmits short pulses of electric current through wires, causing involuntary muscle contractions that incapacitate. Four commercially available TASERs (Tasertron's Model TE86 and Model 95HP; TASER International's Model 34000 "Air TASER" and Model 44000 M26 "Advanced TASER") and a prototype self-contained TASER-like device (Jaycor's "Sticky Shocker") were tested for effectiveness. The output voltage of each was obtained using four different voltage divider dummy loads: 100, 1,000, 5,000, and 10,000 ohms. Eleven minipigs (Sus scrofa) were exposed to the output of each device for 15 sec, with a minimum rest period of 45 hrs between succeeding exposures. All of the devices caused most animals to run in circles. These swine were able to maintain posture and to jump. Rhythmic contractions of the thorax and abdominal muscles were also observed. Only one device, the TASER International Model 44000 M26 advanced TASER, caused a loss of posture (7 of 11 animals). Two of the 7 were able to regain posture while being tasered. The relative effectiveness of the various devices appeared to be related to total charge flux, with the M26 Advanced TASER having the largest value by far. maximizing the total charge flux output from a TASER should be the basis for any program designed to increase the device's effectiveness.