Sensiv Multi-Channel TENS Unit Sensiv Multi-Channel (1236457_CS) 20/CSPlug TENS pads to TENS unit, then attach TENS pads to spots on your body where there are sore and aching muscles: Use unit to select one automatic or one of four manual modes. Use on shoulders, arms, legs, feet, back and joints; not on thorax or upper back. Four modes for different therapy needs Batteries included Pads are durable but replacement pads are readily available when you need them.