At first, I didn't think it was so effective, so I bought a set (not expensive, only 297 sets) with the mentality of giving it a try. Unexpectedly, it was a little hot after only 20 minutes, and it still felt like acupuncture. It's only been worn for a month, and my family said that my back didn't hurt and my rheumatism didn't get worse. I said, I bought it right this time.