With years of clinical usage, there has never been any adverse reaction reported because of the use of either unit.
The units are housed in a portable, watertight, hardened carrying case. They have fuse protection against current overload with external auto shut-off features. They operate at 110 Volts, 60 Hertz (can be fitted to 220 Volts at 50 HZ) with less than ½ Amp power consumption. The units convert alternating current (AC) to direct current (DC) pulses of energy with FM modulation.