Why Choose Our TENS Units? -Compared with other similar tens machine products, we think more for you: With SMART MEMORY FUNCTION: This electric muscle massager will remember your preference of mode setting, you do not need to search from 24 modes again. With CONSTANT STEADY PULSE MODES: Kneading mode 1 and mode 2 deliver stable electrical impulses which not fade in and out every few seconds, designed for those who are looking for a constant steady pulse massager. Our tens machine can use at the same time when you are working or doing housework, which other brands' tens unit can't do. With SAFETY LOCK FUNCTION: To prevent unintentional changes of mode or intensity, our NURSAL tens device adds a lock function. Long press the center button for 3s until the "Lock" symbol appears on the screen. With 90MINS LONGER TIMER: The rechargeable tens ems unit built-in15-90mins timer allows you to control your treatment process up to 90 minutes. A powerful rechargeable battery offers you 30H of continuous usage. PROFESSIONAL MUSCLE PAIN RELIEF DEVICE. This physical therapy equipment is also equipped with independent A/B dual channels, 24 pre-programmed TENS & EMS therapies, each mode with 20 intensity levels to adjust, which can be used for relaxation with the max of 6 pads applied by two persons simultaneously.