Love having this on my key ring! It's easy to use and works well. When you need to find something you just push the button on the transmitter and the receiver beeps and blinks red. The transmitter can be carried around with you, and also has a flashlight that comes in handy. The transmitter needs 2 AAA batteries that are not included. The batteries for the receivers are included.
I did not have much luck with the sticky dots that were included, but I did put one of the recievers on our TV remote. These are really useful at my house. (I have a small child that likes to hide stuff from me.)