Multifunction - Door window alarm deterring thieves effectively by 110dB loud alarm, also prevent children /pets going out the house without notice. Easy To Install - Wipe the flat surface, peel off sticker, mount the alarm on door and magnetic stripe on door frame. Done!! Smart Design - The alarm and magnetic stripe are separated more than 0.39inch(10mm), it keeps going off until you close door(make them connection) or turn it off(switch to the button "OFF"). Power Save – Battery for power supply can be used for more than one year.(without Batteries) Package Include - 4 x Door Window Alarm(without Batteries) Package Include - 4 x Door Window Alarm(withoutBatteries)