Twin Stim Plus has four Channels, eight Electrodes in all, three approach of TENS and three approach of EMS pain relief is on the way. This unit is the grand daddy of them all when it comes to treating larger areas in need. Features & Specifications Twin Stim Plus, Digital TENS/EMS Combo. It has four Channels, Isolated Between Channels. Pulse Amplitude can adjustable in 0-80 mA Peak into 500 Ohm Load Each Channel. Voltage has 40 Volts Peak to Peak on 500 Ohms Load. Pulse Rate adjustable from 1 to 120 Hz. Pulse Width adjustable From 50 to 400 Microseconds. It has Symmetrical Biphasic Square Wave. On Time can be adjustable with 130 Seconds, 1 Sec./step. Off Time can be adjustable with 130 Seconds, 1 Sec./ Step and ramp time can be adjustable with 19 Seconds, 1 Sec/ Step. It can approach 3 EMS they are Constant ,Synchronous, Alternate. It also approach three TENS i.e. Burst, Normal, Modulation.