4 Pack Wireless Door Window Alarm, Magnetic Burglar Alert Sensor, Loud 90lb Door Alarms for Kids Safety, DIY for Home Security, Office Protection

【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"). Size: 2.52" x 1.67" x 0.66, no much space needed to install. It has 2 adjustable settings (on/off).
【ALARM ON AND OFF MODE】 When someone come in and open a door or window, making the gap more than 0.5 inches, the alarm will immediately send out an alarm (high loud, > 90 dB) . If you want to keep the door open, please switch to the alarm off mode.
【HOME AND OFFICE SAFE】Remind you immediately when the pets or someone come in. Prevent theft when no one at home, and the loud alarm will scare the thief so that you can sleep well at night without worrying about the intruders.
【EASY TO USE】Wipe the flat surface, peel off sticker, mount the alarm on door and magnetic stripe on door frame. Done.
【NOTE】1. Need to put in 2 AAA batteries. 2. The small triangle on the side of the strip magnet is aligned with the small triangle on the side of the alarm with a spacing of less than 0.39inch(10mm), 3. Your frame and window or door must be flush, make these two components must be installed very flush with one another.

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