Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Not mature product

It looks like good when you buy this product new. However, it works only for a couple of weeks, then noise comes; the longer the more, and finally, you cannot tolerate and have to give it up. I have bought this product for six months and threw it away. My conclusion is that this is a not mature product on the market. Don't buy it. The manufacturer should make more lab research before put it into market.