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Security Alarms, Door Sensors and Accessories

Window and door alarms, entry sensors, alarm lights and buzzers, plus the connectors, guards and replacement batteries that go with them. 107 products from $3.99 to $168.99. MPF Products, Acuity Sensor Switch, Safety Technology International and more.

107 products from $3.99

107 results · page 1 of 2

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Sensors, sounders and the parts that keep them running

Devices here fall into a few jobs. Sensors detect an opening door or window or movement; sounders such as buzzers and alarm lights announce it; guards and covers protect call points from accidental use; and cables, connectors and batteries keep the system powered. Decide the job first, then whether you need a stand-alone unit that alarms by itself or a part that must work with an existing control panel.

Power, voltage and compatibility traps

Alarm gear runs from mains-fed low-voltage supplies, from battery packs, or from a built-in battery, so read the power line of each listing. Many low-voltage devices and CCTV-style accessories use 12 V DC through a barrel-style lead whose polarity and plug size must match. Replacement packs must match voltage, chemistry and capacity in mAh, for example nickel-zinc against lithium-ion. Wireless sensors only work with a receiver on the same protocol, so check compatibility with your panel.

Questions about Security Alarms, Door Sensors and Accessories

Do wireless door sensors work with any alarm panel?
Not automatically. A wireless sensor talks to a receiver or panel on a matching frequency and protocol, so one brand's sensor often will not pair with another's system. Choose sensors listed as compatible with your panel and check the signal range inside your building.
How do I choose a replacement alarm battery?
Match the voltage, chemistry, capacity and connector. A 12 V sealed pack and a 3.7 V lithium cell are not interchangeable, and the pack must physically fit the housing. Capacity in mAh sets how long the alarm can run on battery power.
What is a stand-alone window and door alarm?
A self-contained unit with its own sensor, siren and battery that sounds when a door or window opens, or when it detects vibration or movement, depending on the type. It needs no panel or wiring, which suits apartments and rooms where a wired system is impractical. Check its rated sound level.