YoLink LoRa Smart Door Sensor Starter Kit: - 1/4 Mile Open-Air Range, Door Left-Open Reminders,5 Years Battery Life, SMS/Text, Email & App Alerts, Alexa, IFTTT, Home Assistant

A SMART START! Everything you need to get started: one YoLink Hub and four Door Sensors. Batteries are included and preinstalled, good for up to 5 years between battery changes. Supports 300+ devices from our full product line. Add more hubs for large homes, high-rise condo buildings, etc. WHY PAY A MONTHLY FEE, when you can secure it for free? Self-monitor and save when you take advantage of our many ways to be notified of alarms and off-normal events in and around your home or business. See "Know Now!" for more information!

THAT WAS EASY! Installs in moments: scan the sensor's QR code, give it a name, peel off the pre-applied 3M brand mounting tape protective plastic, press the sensor and magnet to the door and frame, and you have added security to your home or business!

MORE THAN JUST A DOOR ALARM! Place a sensor on each exterior door and window to "Protect Your Perimeter" Activate and control lighting. Place a sensor on your fridge/freezer door or lid and know if it was left open, to prevent food loss. Track activity in your home or business. Keep an eye on children and elderly loved-ones. Use the sensors to protect liquor & medicine cabinets, gun safes, storage lockers & boxes.

DOOR AJAR! Our unique Door Left-Open reminder can be used to alert you to a door or window left open too long! You define the maximum time. Use our SpeakerHub, our audio hub, to play a tone or message, alerting you when a door is opened or left open too long.

NOT YOUR FATHER'S DOOR SENSOR! This is a sophisticated electronic device, utilizing the latest technology. 24/7 cloud server device supervision monitors your system for online presence, signal strength and battery level, to ensure it will work when you need it! (Hub required, for full functionality)

DEVICE-TO-DEVICE PAIRING: a unique feature, two or more devices can be paired together. Even if the internet is out and the power is down, they will carry out their paired actions. Pair your door sensors to a Siren Alarm, then turn it off when you want to "disarm" your system. Use a SirenFob or FlexFob to control your siren. Make your own custom security system!