"I am a flight attendant. This gives me an extra sense of security when I am at a hotel on a layover. Through the years there have been reports of people’s rooms being accessed. I sleep much better with this under the door. These work great for blocking doors. Once the door stopper is in place, an alarm will sound if the door is opened. The alarm is a screeching sound and it will most likely wake you if someone tries to breech the door."