AIWOTOWOW Doorbell Portable Plug-in Wireless Door.

This door bell is easy to install just put it where you want it in an electrical socket. It runs on electricity. Once you find the perfect place in home, office, hotel, or etc just pick you ringtone / ringtune you would like best and leave it there. I went through all of them twice before I decided on one that I really liked. You can also turn up the volume on it or turn it down. On the door bell itself it will light up a blue light when it's ringing. It's really loud in my three bedroom house. I wanted it for when the mail gets delivered or friends pop over unannounced and need to ring it.

I received it at no charge / deep discount in exchange of an honest and unbiased review.