The inside flip top cover includes an instruction diagram to guide the user through 3 modes of operation; constant, cycle, and reciprocal. On Time, Off Time, On Ramp and Off Ramp are available. A timer allows the patient to use the device for a specified period of time and a low battery indicator light illuminates when the 2 AA batteries (included) need to be changed. If the device is not correctly attached to the patient, the amplitude does not increase. The device has a patient lock that also can be used as a patient compliance meter. Dual channel, with Biphasic Rectangular waveform. Measures 4.2" x 2.9" x 1.4" (107cm x 74mm x 40mm); weight 3.5 oz (94.97 grams).