This compact motion sensor will detect anyone who attempts to enter the protected area. If motion is detected a powerful 130 dB alarm will sound to scare off the intruder and alert others to your need for help. The owner may arm or disarm the unit using a programmable security code. Ideal security for home, retail store, office, or hotel room. An optional External Siren (Item ES35) is sold separately. Requires four “AA” batteries.