yolink smart home starter kit: 4 door/window sensors & hub kit, compatible with alexa, ifttt, app for remote monitoring, control and alerts, door still open (door left open) alerts yolink product requirements:<br> the smartphone or tablet able to run ios 9 or higher; android 4.4 or higher.<br> <br> features:<br> real-time status - monitor the real-time state of door via yolink app. <br> open remind - remind you while the door is open for a set up time. <br> battery status - update battery level and send low battery alert. <br> yolink control - trigger an action of certain yolink devices without internet. <br> automation - set up rules for “if this then that” function.<br> <br> specifications:<br> yolink hub<br> input: 5v dc<br> maximum current: 1a<br> working temperature: -20°c~50°c (-4°f~104°f) <br> humidity: 0~90% non-condensing<br> <br> yolink door sensor<br> button: set button<br> voltage: 3v dc (2* aaa battery)<br> trigger distance: 18-25mm<br> environment: <br> operating temperature: 0°c~40°c (32°f~104°f) <br> storage temperature: -20°c~70°c (-4°f ~158°f) <br> operating humidity: 10%~90% (non-condensing) <br> storage humidity: 5%~90% (non-condensing)<br> <br> package content: <br> 1 x yolink hub<br> 4 x yolink door sensor