This product can be used as a wireless door chime but has many other uses. Leave the receiver on whatever you wish to locate such as your house, chair, basketball hoop or beach blanket and carry the transmitter. By pushing the button, the receiver plays a tune at 85 dB, which is quite loud or it can be set to only flash a bright red light. The receiver uses a 9-volt battery (included) and the transmitter runs on 2 AAA batteries. It has a 100 foot range when there are not obstructions. Comes with screws for mounting the transmitter or it can be worn on a belt using the belt clip.