This is the one that I have. A friend gave i t to me. The pads are super sticky and the battery life good. https://omronhealthcare.com/products/pocket-pain-pro-tens-unit-pm400/ This said, I need something stronger. I use it on my lower back and need more intensity to feel relief. Keep in mind that when I use to see the PT I was all for them cranking up the intensity level of their medical grade tens unit.
Is yours water spray friendly? The one I purchased uses water sprayed on the circulation booster base unit, ones feet, and also recommends spraying the sticky pads for more intensity too.
Honestly I don;t know. The packaging was tossed before I had a chance to read it