The Compex Performance 2.0 Muscle Stimulator Kit with TENS is recommended for the fitness enthusiast and the athlete who engages in frequent competition. It features a total of 6 programs, with 5 levels of progression to help competitive athletes achieve the highest level of performance. The Endurance Program increases muscle capillarization and establishes a working regimen for oxidative power of endurance muscle fibers; targeting slow-twitch muscle fibers. The Resistance Program targets both slow and fast-twitch muscle fibers; building muscle size, strength and density. The Strength Program targets fast-twitch muscle fibers. This program increases sheer strength, and works the muscles at maximum power with less risk of injury to joints and tendons, with virtually no cardiovascular or mental fatigue. The Active Recovery Program does not contract the muscle. This program clears lactic acid, increases blood flow, promotes muscle relaxation and enables faster recovery. The Pre-Warm Up Program does not contract the muscle. It runs at a low frequency and increases blood flow and oxygenates the muscles prior to a workout or competition. The Compex Performance Muscle Stimulator kit includes a carrying case, battery charger, CD with user manual, electrode placement guidebook, and one set of 4 Easy Snap Electrode lead wires. This kit also includes 8 of the 2" x 2" Easy Snap Performance Electrodes and 4 of the 2" x 4" Easy Snap Performance Electrodes. Electrodes are the points where the pulses are transmitted to your motor nerves, and ultimately your muscle fibers. They play a big part in the Compex muscle stimulation session, allowing you to work your muscle at peak effectiveness. Each Compex Easy Snap Performance Electrode is coated with a strong medical-grade adhesive, developed to stick to your skin. When used in normal circumstances, each electrode should last 15 to 20 sessions.