Some people find that the zappers burn the skin. Therefore you have to keep moving it around. Some people don't find this. It depends on the ph of your body. I think the more acidic you are the more it burns. The burns are minor and you just move the zapper when you feel a tingle. I am wearing the T2 now and just had to move it.
There are quite a few posts on here where people new to zapping got burns. The advice is to put the zapper on the soles of your feel secured with a sock or support bandage. The skin is thicker there and it shouldn't burn.
If you are ill enough a few small tingly burns won't put you off. When I started using the zapper I had terrible heart pains and stuck it on my heart straight away. I felt some pain in that area but after 3 mins it went away. Basically I think it really helped me and not only that it gave me hope when the doctors had just said please do visit us again the next time you have serious heart pains. At that point I realised I didn't want to be visiting them again and certainly not with heart pains.
Yes the zapper may or may not burn your skin it did mine. I also had no idea before I bought it that it may burn.