This is the Add On XT Weatherproof camera for users with existing Blink Remote Home Security and Video Monitoring systems. It includes the camera only and must have a Sync module to operate. If you are new to our Blink Wireless Home Security and Video Monitoring system, please start with the purchase of one of our full system bundles consisting of 1, 2, 3 and 5 camera system packages. For existing Blink customers, the XT camera works with your existing Blink system and sync module! Blink is a 100% wireless, battery-powered and amazingly affordable remote home security camera system that sends real-time alerts to your smartphone with motion-activated video clips. Customers watch motion-activated video clips or live video feeds right on their iOS or Android device and install it themselves without having to hire a technician. No Monthly subscription fees either!