I replaced an old analog Tens with the 7000. It’s small lightweight, digital and easy to use. The pads are very sticky at first but like anything disposable you need to replace them periodically. They aren’t expensive. The adjustments are very easy and it locks after a minute or so which prevents accidental zapping yourself if you happen to bump into something. So far it has definitely helped my back. Helping with pain and muscle spasms. Hopefully it will be durable. Time will tell. I already recommended it to a friend who had a shoulder replacement and she is returning a CVS tens which was much larger and more complicated to use. I got the rechargeable model with a bunch of extra pads. Highly recommended.