Increase your sense of security with Tellur's WiFi Smart Door & Window Sensor.   Working with classic AAA batteries, the sensor has a low energy consumption and a battery life of up to 6 months. Once connected with the Tellur Smart app, you will receive notifications directly on your smartphone when the door/window is opened/closed, the batteries are running low and, most importantly, when someone tries to destroy or detach the sensor. The history record helps you keep track of the days and hours when the door/window was opened/closed. The WiFi Smart Door & Window Sensor is only compatible with 2.4GHz WiFi frequencies and can be voice activated through Google Home and Amazon Alexa.   Power supply  :  2 x AAA battery, 3V   Battery life  :  Up to 6 months   Open/Close notifications  :  Yes   Tamper notifications  :  Yes   Low battery notifications  :  Yes   History record  :  Yes   WiFi standard  :  IEEE 802.11b/g/n   Supported WiFi network  :  2.4GHz   Dimensions  :  7.5cm x 4cm x 1.8cm   Weight  :  65 gr   Color  :  White   Package dimensions  :  7.8cm x 4.2cm x 4cm   Package weight  :  85 gr   Package includes 1 x WiFi Smart Door & Window Sensor 2 x Adhesive tape 4 x Screws 2 x AAA batteries