Blink Outdoor 4 (4th Gen) ? Wire-free smart security camera, two-year battery life, two-way audio, HD live view, enhanced motion detection, Works with Alexa ? 4 camera system Outdoor 4 is our fourth generation wire-free smart security camera that helps you protect your home inside and out right from your smartphone. See and speak from the Blink app ? Experience 1080p HD live view, infrared night vision, and crisp two-way audio. Two-year battery life ? Set up yourself in minutes and get up to two years of power with the included AA lithium batteries. Enhanced motion detection ? Be alerted to motion faster from your smartphone with dual-zone, enhanced motion detection. Person detection ? Get alerts when a person is detected with embedded computer vision (CV) as part of an optional Blink Subscription Plan (sold separately). Save and share clips ? Choose to store events in the cloud with a free 30-day trial of the Blink Subscription Plan or locally with the Sync Module 2 (included) plus a USB drive (sold separately). Works with Alexa ? Connect to an Alexa-enabled device to engage live view, arm and disarm your system, and more using your voice. Includes four Outdoor 4 cameras, one Sync Module 2, eight AA lithium metal batteries, four mounting kits, one USB cable, and one power adapter.