Small Stungun Mini Self Defense Stun Gun Cheetah StungunsStun guns have evolved to become more effective, safer to use, and more discreet. Newer models such as the small stungun, mini self defense stun gun, Cheetah stunguns, and pen stun guns are capable of generating up to 2.7 million volts -- enough to floor an adult male and leave him disabled for approximately 20 to 30 minutes.