In some cases you are in a state of terror and will prefer something that is going to protect you all of the time. You need to think about this since you are deciding how you are going to stay as alert as possible.
The keychain alarm is crucial in this day and age.
You need to think of what you are using to protect yourself, and this would be the ultimate alternative. It is effortless to connect, and you will be able to stay safe.
I use it continuously, and it does a good deal for me. You need to have one for yourself too.