Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Wish I had read these reviews before I bought

All this air pump does is let out what little air may be in your tyres. I can't think of anything else I have ever bought that was as completely useless as this. It is a toy, pretending to be an air pump. The nonfunctional lever on the top (mentioned by other reviewers) indicates that it was designed as a toy. I'm just happy I was trying to put air in my tyres in the driveway, not out on a trail. In the past, I have bought a number of Bell products, including motorcycle helmets. I now shudder to think what might have happened if I had put one of them to the test.