It was very bright and stylish, and it was easy to install and easy to operate, but it did not turn on at around 3 months after use. Did the test battery run out? I thought I tried replacing the battery but it did not turn on. When looking carefully, the circuit part was rusted and rotten. I was convinced that it was waterproof for bicycle, but it seems that it was not waterproof. Those who think about using in bicycle attachment think that we need attention.