My son got this siren for 4.Geburtstag for his bike. The bracket is a bit difficult to assemble because the screws attached some were too short and it will quickly loose. Have a longer screw taken from us and it was good. Therefore deduction also a star. The siren itself is really great tones with four different and switched-light. My son is very enthusiastic and leaves every day with his bike and play with the siren or police. Once it is there something darker that's light can be seen better than sunshine. Battery can be change easily, just up this way central cover then press it down to make again. No screws needed. Has also been raining quite a few times and still worked without any problems. Nevertheless, it does not have to be permanently exposed to rain. For small police an absolute highlight.