3 TENS Modes and 3 EMS Modes. Variable pulse rate and width. Variable ramp time. Variable contraction/relaxation time. Wave: Symmetrical bi-phasic square pulse. 2 timers and compliance meter. Comes with 8 electrodes. Unit can be powered by either AC adaptor or 4 AA batteries. Includes: Stimulator, 4 Lead Wires, 2 package of high quality Self-Adhesive Electrodes, 4 AA batteries, AC adapter, Soft Carrying Case, Instruction Booklet.