Thera 3+ by ProActive is a 3-in-1 (TENS, EMS & massage) device is rechargeable with 78 pre-set programs along with the ability to fully customize treatment options. It has a large, easy-to-read LCD and includes all accessories. The Thera3+ Dual channel TENS Electro-Stimulator relieves pain in 3 ways: TENS (Transcutaneous Nerve Stimulation) stimulates or numbs nerves. EMS (Electrical Muscle Stimulation) prevents muscle atrophy. Massage soothes sore areas.