In the beginning I was a bit skeptical that this might not be a good fit for my STIMTEC Tens and EMS machine. I tried to make sure the size of each connector (measured in mm) matches the recommended measurement in the guide. Because the description did not confirm if it fits the machine, I hoped it would. When I got it, I tested and I could not be happier. It worked perfectly. Now I have enough supplies for sometime and I can continue to get the therapy I need. The cost of the whole package was also reasonable in my view.