I love this device. Have been using on my pup for one week plus everyday and she isn't limping anymore. She also has a cruciate ligament injury and some days you can hear a clicking noise and most of of time we don't. I also hurt my wrist, not sure how and used it on that pain and it was gone the next day. Very impressive. I did contact seller because I was afraid it may hurt my pup, he assured me it wouldn't. It does not make your skin hot or anything. I read directions twice. This is a must have. So glad we bought it. Has a one year warranty that we registered for as well. Great product. Very impressed.