I like the appearance of these and the size as well. They are loud and should definitely alert if there is an issue and scare off an advancer - I say should because IDK how other people will react. My only worry is that the pin on the side will come out too easily maybe and the alarm will go off when there are no issues. I bought this as a gift for my friend and her daughter as they are both out late a lot and I worry about their safety.