$30 · Home security alarm

I bought these because my son has autism and I was trying to know when he left his room but it is too loud for this purpose because we are in a 4-plex. Works absolutely great because I tried one of them and left two in the boxes. They are wireless and easy to set up and they use magnets that when disconnected set off the alarm. Great for front doors or gates or anywhere else that you want to be alerted when somebody comes in. One for $30 or two for $50.