The 2-PackAlarm System Set offers a simple yet effective security solution with no tools required for installation. Each unit features a magnetic sensor that triggers a 90dB piercing alarm when the connection is broken. Powered by three included LR44 batteries, this system ensures reliable operation. The convenient peel-and-stick installation makes setup quick and hassle-free, providing enhanced security for doors and windows in minutes. Comes packaged in a blister pack. The alarm measures 1.5" x 2.5". The package measures approximately 6.90" x 5".,Alarm System Set,Alarma 2Pzas.