Features:Mini shape and decent appearance， 4 alarms per pack.Wireless unit without any cords.Super loud 105 db alarm sound.Electronic magnetic sensor detects entry.Alarm with ON / OFF switch for easy operation.Burst into alarming if someone opens the door or the window.The alarm will stop alarming when the two parts recombined.Easy to install， just peel and stick.Ideal entry warning for homes， apartments， mobile homes， dorms， offices， hotel rooms， garages， and more!Specifications:Alarm volume: 105 dBBattery: 3 * LR44 1.5V button cells (not included)Per alarm weight: 25g / 0.9ozPer alarm size: 21 * 35 * 54mm / 0.8 * 1.4 * 2.1inPer magnet weight: 10g / 0.3ozPer magnet size: 50 * 13 * 11mm / 2.0 * 0.5 * 0.4inPackage size: 21 * 14.2 * 2.5cm / 8.3 * 5.6 *1.0inPackage weight: 106g / 3.7ozPackage List:4 * Magnetic Alarms4 * Magnetic Sticks