Now you can record a message that will be heard by you or your loved ones whenever a light switch is turned on or off. You can set the unit to lock in your message or set it to change the message with a simple touch of a button. Records a message up to 20 seconds long. Great for every room in the house. In the kitchen you could record a message to yourself like: "Don't be tempted to open the refrigerator, remember you're on a diet". In the living room you could record a message to the kids like: "Don't forget to finish your homework before watching TV". In the bathroom you could record: "Don't forget to brush your teeth and hang up your towel". A father could record a message in his daughter's bedroom like, "Kathy, I will be at your soccer game tonight. See you then. I love you, Dad". So simple to use even children can do it. You just touch of a button and record the message. Simple to install-no wiring just replace the existing single switch plate cover. A red light come on while you are recording and goes out when maximum recording time is used. Length of message can be up to 20 seconds. Size: 5 inches by 5 inches by 1/2 inch thick. Mounts with two screws (included). Requires 4 "AAA" batteries - not included