I bought it to relieve my back. I'm not sure he really has an effect on back pain, for against, I find it very relaxing, I use to sleep at night. I put it straight into my bed and I spend a good twenty minutes on it. It relaxes me enormously. In receiving I did not be able to lie down on the pins, and in fact they cause no pain: they heat up just a little for a few minutes. My young children also extend it to imitate me, and do not find that either painful. It even happened to me several times to sleep on it ... I measure 1m78 and I took the size 2. Looking back, I think the smaller size would suffice.
