Sends small, comfortable electrical impluses through the skin into the painful area causing a mild tingling sensation. The sensation works to prevent pain signals from reaching the brain. Features two channels, allowing it to operate two pairs of electrodes for better focus and deeper tissue stimulation. Waveform is symmetric biphasic square. Carrier frequency is 4,000 10% Hz, fixed. Difference frequency is 1 0.5 150 10% Hz, adjustable. Pulse width is 125 10% s. Timer range from 15 or 30 minutes to continuous mode. Specifications Channel Dual Carrier Frequency 4000 10% Hz, fixed Difference Frequency 1 0.5 150 10% Hz, adjustable Output Voltage One pair 42V 10 peak into 500 Ohms load Two pair 30V 10 peak into 500 Ohms load Wave Form Symmetric biphasic square Timer 15, 30, continues Power Supply 9V Alkaline battery or adaptor Four Frequency Shift Continuous, 1/1 abrupt, 8/8 abrupt, 10/10 ramped options. Includes IF Unit Four 4 Electrodes Two 2 Leadwires 9V Battery, type 6F22 9V DC Adaptor Instruction Manual Carrying Case 1 Each / Each