[REQUIREMENT FOR USE]: As the accessory of Linkind Home Security System, it MUST BE EQUIPPED with Linkind Siren Hub(in Security Kit) or Linkind Mini Hub to get it work: Siren Hub for home alarm system and smart lighting, Mini Hub only for smart lighting. Connected devices sold separately. Compatible with Alexa Echo (only 4th Gen), Alexa Echo Plus (1st Gen, 2nd Gen), Alexa Show (only 2nd Gen), Alexa Echo Studio if you don’t have a Linkind Hub..[WIRELESS DOOR WINDOW GUARD]: Get the sensor connected with Linkind Siren Hub(SOLD SEPARATELY), it is able to detect unexpected break-in of your door or window, sending real-time alert to your Linkind APP and trigger the siren hub to sound high-pitched alarm. “Open”&”close” status will be recorded in real time on the APP..[AUTOMATION WITH LINKIND SMART LIGHTS]: Want the light be switched on when you open the door back from work in the evening? Set up the sensor with Linkind Zigbee Lights(SOLD SEPARATELY and HUB REQUIRED), explore more automation on Linkind APP..[EASY SETUP AND ANTI-TAMPER]: Adhesive tape and mounting bracket available for easy installation. The anti-tamper design will alert you through the APP if intentional removal of the device occurs..[BATTERY INCLUDED]: The lithium battery is included and replaceable. It has a battery life of up to 2 years. The indicator of the sensor or the APP will indicate you if the device is in low battery.