Instruct: Classify the given review into positive or negative sentiment.
Query: Doesn't stay on!

I was all excited to try out my new Pro-Tec Knee Strap. I put it on before my workout and everything seemed great, it fit perfect. But the moment I started running it fell off. I put it back on and it fell off again and again. So I decided to try it another time when I was taking a class at my gym and sure enough as soon as I started to move around, anything more than walking I could immediately feel it slipping. The Pro-Tec Knee strap seemed great, but not if you want to use it to work out. I guess I will just order a new TruFit Knee Strap. I've used one for years and loved it, but it needs to be replaced and now I'm regretting trying something new.