Review on 5-Pack EBL 9V Rechargeable Lithium Ion Batteries With 600MAh Capacity And 5-Bay Charger For Smoke Alarm Detectors - 2A Input by Alexander Chavis

I bought this to use the batteries with my TENS unit for my back. All batteries came sealed and the unit looks like its made well. I did not realize it is a USB charger. It barely gets warm after they are on a full charge. I didn't reach over to check during the first 2 hours when they would have actually been charging. But 4 out of 5 batteries were supposedly charged according to the green lights. One did not take a charge but I am assuming it was not seated correctly. I am unable to test them at this time because my tens unit is now fried! I don't know if one of the batteries I tried killed it or if it's just bad luck/timing. I was using the InTENsity 5000 that was about 3 yrs old that was bought under a prescription. Now I am looking for a replacement that takes 9-volt batteries and the same style of electrodes or "pads" since on the same purchase I had ordered 40 pads. ;/ I will update the review as soon as I can test things out.