I am a retired Registered Nurse. I tend to avoid pain meds whenever I can and lean towards utilizing alternative options. I have used these microcurrents quite successfully for many years. I always make sure that I have at least 2 in my first aid area at home. They last a long while, and I also ordered (from a different supplier and different brand: Mini TENS Supply Kit, AccuRelief) extra reusable self-adhesive pads because the pads sometimes need replacing before the battery is dead.
These are GREAT for back pain when I've strained my lower back. I wear them all day and night when it is acute, and it really does help. Then I remove them and put them away for the next time! Unlike a TENS unit, you do not feel these when they are on, as they don't contract your muscles, yet they slowly, over hours, help bring relief. Sometimes I've used 2 at once to cover more area of my back. I have a mild to moderate scoliosis so I'm vulnerable to back strain.
My husband has also used them successfully with acute back pain due to overworking.
These are just a great thing to have on hand when you need them. I've only been able to find them online. I also like that the microcurrent helps the tissues in their healing process.