Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Wasted $20 - Poor Design!

The mirror attaches to the arm by a small ball joint, which is very loose. It was stiff enough to hold the mirror steady while riding, but it was loose enough to very easily pop right out of the socket when lightly bumped with a hand while wiping my brow. It popped out several times, and each time, I was lucky enough to find the mirror part on the ground and pop it back in, until this morning. I have no idea where the mirror went to when it popped out, and now I'm left with a useless $20 plastic arm attached to my helmet. Very poor design. I wish I had read the bad reviews before purchasing this.