KERUI 2 IR Beams Wireless & Wired Infrared Barrier Detector 20 Meters For Home Yard Door Gate Security Alarm System 433MHz, Work with GSM PSTN Alarm system Wireless & Wired Intelligent 2 IR 20 Meters Beam Detector For GSM PSTN Home Alarm System PS: This wireless & wired outdoor 2 beams IR infrared barrier detector CAN NOT WORK ALONE and it must work with Wired / wireless alarm system (all of the alarm systems can work with this item) ,if you want to order this detector to work with the alarm system you buy from other seller,you'd better contact us to more detail to make sure if it can work normal or not. You can use our product both in and out the product of high-tech modem aptitude, it is easy to handle, beautiful appearance. It can be applied to some important places such as department, school, villa factory etc. It can be installed in fence, door, window, balcony, protect and give an alarm. Protect the safety of you and your belongings. PS : Not all the IR Beams detector can work with your alarm system,please let me know what kind of alarm system in your hand before you order. It must work wit the alarm system.