Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Beware of the Spineworx!

I bought it, I tried to use it, my back was in so much pain. It's very hard and presses on your spinal cord, causing pain. U may need to seek medical help if you use this. I wouldn't recommend this to anyone. If you're having back problems, don't try to heal yourself. Seek medical professional help only.