Duo is a one-to-one video calling app for everyone designed to be simple, reliable and fun so you never miss a moment. Features: Simple interface Pick a loved one and jump right in, with a simple interface that brings video to the forefront. Knock Knock See the caller before you pick up with Duos live preview feature. High quality video Experience faster and more reliable video calls whether youre on Wi-Fi or on-the-go. Cross-platform Video call all your friends across Android and iOS with just one simple app. *Data charges may apply. Check your carrier for details.