Sometimes it hits correctly, sometimes not at all, or sometimes it hits 3 minutes earlier. The design and material are fine

I have been using it continuously for a month. I haven't had any problems. The only thing I can say is that when I set it for a very short time, for example 5 minutes, it doesn't hit as hard as when set for 10 minutes or more. Other than that, I am very satisfied.

It is not so loud that you can hear it from far away, you have to have it in your pocket. Other than that, it is average.