It is stuck on a cell phone, a flashlight, a radio, an emergency carrying backpack etc so that it can be easily seen at the time of a power failure such as an earthquake or a typhoon.
From Japan
On 2016-05-03 09:36:22
It served very much at the time of the next earthquake. We had a power outage due to the seismic intensity 7 earthquake, I heard the flashlight falling on the bed rolling down, I was worried about not being found. I have sticked a seal on all flashlights before, and prepared for each room. So, with flashlight, evacuation was made smooth. If it is equipped, it says no grief. I ordered and sent it to my elder sister couple immediately, thank you very much.