This compact, easy to install motion detection alarm made by Intermatic (a recognized leader in the security industry) can be used to protect homes, apartments, businesses, hotel rooms, etc. It will detect anyone who attempts to enter a protected area. If motion is detected a powerful 110 dB alarm will sound to scare off the intruder and alert you to the attempted entry. The owner may arm or disarm the unit using a programmable security code. It has a 30 second exit delay and a 10 second entry delay. For added protection one window security sticker is included. Requires four AA batteries that are not included. This unit measures five and three-eights by two and three-quarters by one and one-quarter inches.