Contrary to some other reviews I didn't have a single problem. It works great and it's nice to know the temperature is perfect before stepping into the shower. To "wake up" you have to move the shower handle, so a fixed holder is not suitable for this. I had to find out what temperature was comfortable for me and that was my goal from that moment on. Also, the red light is a good warning for very hot times. The package also included a spare battery pack which I have not used yet.