[Portable Rechargeable Lithium Battery] The TENS machine muscle stimulator can be recharged via a USB port connection to a wall charger, mobile power, or USB port on a laptop. The battery of the electrotherapy machine has a level indicator that doesn't worry about treatment interruption for dead AA batteries any more. Reusable cable ties of electrodes muscle stimulators solve the trouble of messy cables. Note: Make sure the pad is in full contact with your skin before adjusting the intensity. [4 Different Sizes of Ultra Sticky Replacement Pads] The physical therapy equipment electrode pads made of low-impedance solid gel have strong conductivity and good self-adhesiveness and can be reused 45 times. Three sizes of electrode pads can meet your various needs. The back pain relief device comes with a dust-proof drawstring storage bag, easy to carry so that you can easily use the electrode muscle stimulator for TENS therapy at any time, pain management, and muscle relaxation. [Independent Dual Channel] This electric massager is designed with mutually non-interfering A and B channels, so you can set different modes and intensities for each channel to meet the needs of different parts of the body at the same time. This makes the Bisnik dual-channel physical therapy equipment much easier to use than another single-channel simulator machine that requires manual settings for pulse frequency and pulse width. Simple buttons can be easily operated even by the elderly. [24 Modes with 10 Stronger Intensity Levels] The muscle stimulator machines are built in various user-friendly easy-to-use pre-programmed 24 preset massage modes and 10 to 60-minute timer controls. Each mode of the TENS device has 10 intensity levels, LCD blue light eye protection screen is easy to adjust, and powerful strength can quickly help relieve common pain like neck pain, carpal tunnel relief, arthritis, and shoulder, knee, elbow, leg, and foot pain. [Fast and Accurate Pain Relief] Bisnick TENS machine adopts human body simulation massage technology, integrating the TENS unit, TENS EMS unit, and muscle massager, effectively stimulates sensory nerves, helps relieve pain associated with sore muscles due to strain from exercise or normal household work activities, and improves muscle performance.