Russian Muscle Stimulator 3500One of the only portable Russian Stimulators available, the Russian Stim 3500 is a dual channel electro stimulator with a symmetrical biphasic square waveform. While this unit functions very similarly to standard EMS units, it has a higher frequency of 2500 Hz, which enables the electrical signal to reach deeper into the muscles for a more effective contraction of the muscle fibers, making this unit particularly beneficial for athletes looking to tone