Contains 2 electrode pads & 1 replacement battery. For use with SmartRelief control unit (sold separately). Blocks even chronic pain signals. TENS therapy. Powerful, portable pain relief. Relieves even chronic pain. For tough or persistent pain, it's often difficult to find relief. Now you can get the same TENS technology used by your doctor, for a fraction of the cost and without a prescription! For persistent sore or aching muscles. For relief of chronic pain associated with arthritis. Convenient: Includes an easily replaceable standard 3V (CR 2032) watch battery. Safe & Effective: Drug free. Blocks pain signals at the nerves. Energy Saving: Automatic shut-off after each 30 minute session. Reusable: Control unit, electrode pads, and battery are all reusable. Discreet & Portable: Use while doing normal activities. Personalized Relief: Intensity is adjustable (63 levels). Convenient; safe & effective; wire free; reusable; discreet & portable; personalized relief (63 levels). Made in China.