2-in-1 Motion Sensor Alarm and Chime: * Infrared motion sensor technology * No installation required * Panic button activates the alarm * Includes 1 mountable alarm unit and 2 remote control units * Measures: 4.75"L x 3.75"W x 1.75"H * Requires 4 double AA batteries (not included) * Each remote requires three 1.5V batteries (included)