Bought this as it was the upgraded version of the one my pain management team at the hospital had lent me to try I wouldn't use any other brand tens machine now easy to use pads are easy to get hold of and just a 9v battery to change when needed it's a great bit of kit

For those who are looking for reviews to see if this really works, I can whole heartedly tell you the answer is YES! I'm using mine as I write this review.
This is not a permanent cure for pain, but if you suffer badly, it does give some very welcome relief.
I have, at the age of 47, osteo-arthritis, most noticeably in my knees. I have had an upper tibial osteotomy, where the metal plate snapped, and took some bone with it, so had the operation a second time, with the addition of bone graft taken from my hip. So, with one knee repaired, but still painful, and the other, unrepaired, and having taken a beating whilst I was on crutches for the best part of a year, I have a pretty good idea of how much difference this can make.
You get plenty of easy to understand information regarding settings, placement of electrode pads, alternative placement, as well as some reusable pads to get you started. The pads supplied can be used many times, and replacements are pretty reasonable to buy on amazon, especially if you buy the 24 pack.
How TENS works, is by disrupting the signal your body sends, from the pain area to your brain. The pain is an electrical signal that travels through your nerves and muscle. What the TENS gizmo does, is to send a fluctuating pulse across the path of the pain signal, so that little or no pain gets through. If you imagine a long thin warehouse, with a man shouting to a second at the other end. If you were to add two more men at the halfway point, and at the sides, one beating on metal, and the other using a circular saw on wood, then the sound from the shouting man would be lost, and not reach the other end. (Best way I could think of to explain it)
What you actually feel is a tingling sensation, which increases as you turn the dial up. It is only painful if you turn it up way too far, so turn the dial slowly until you find your comfortable point.
If you wonder how easy it is to use, well my technophobe 78 year old mum can use it, and she gets confused by the Sky box. ( Sorry Mum)
Places like Lloyds or Boots chemists sell various makes and models of TENS units, from cheapish, to bloody expensive, but in my opinion, unless you need to treat more than two areas of pain at once, this is as good as any, and more reasonably priced than some.
I really recommend this, as it give you at least a bit of respite from pain.
Good luck to all who are looking at this, and have a need for it.

Loads of different settings and options so had to get professional advice from physio over how I should be using it but easy to use and works well.

Its all good works good

Purchased because of medical needs and it fulfills those needs to the letter.
Easy to use, easy to follow instructions.