Google started rolling out its video chatting app, Google Duo, in 78 languages on Monday, Aug. 15. Available for both Android and iOS devices, the “1-to-1 video calling app” promises to make video calling simple. While Google Duo's interface is reminiscent of Apple's FaceTime, the video calling platform has its own unique features and limitations from other video calling apps.

Unlike other Google apps, users do not need a Google email ID to use Google Duo. Simply having a phone number will allow the user to video call individuals in their contact list who have the app. Contacts who don’t have the app can be invited via a text message with a link to download Google Duo.

The streamlined setup process makes Google Duo more appealing than other platforms that require an account (say, Facebook Messenger) and being device-centric means iOS and Android users can video chat with one another — unlike Apple’s Facetime which only supports iOS to iOS calls. One limitation; however, is the lack of group video calling abilities on the app, which is available on other competing apps (e.g. Skype) and even on Google Hangouts.

But Google Duo has a feature that makes it unique from others on the market. When an individual receives a call, the app’s Knock Knock feature lets the chat recipient see live video of the caller for some visual insight. Google says Knock Knock makes video chats “spontaneous and welcoming,” but it could potentially help users avoid uncomfortable conversations or prioritize an emergency call.

Google Duo, which was announced in May at Google I/O, transitions between Wi-Fi and cellular data without dropping calls, according to Justin Uberti, Google’s principal software engineer.

“We’ve built Duo to be fast and reliable, so that video calls connect quickly and work well even on slower networks,” wrote Uberti n a blog post. “Call quality adjusts to changing network conditions to keep you connected — when bandwidth is limited, Duo will gracefully reduce the resolution to keep the call going smoothly. For video calls on the go, Duo will switch between Wi-Fi and cellular data automatically without dropping your call.”

Similar to its competitors on the market, Google Duo offers end-to-end encryption for all calls. This means nobody aside from the two parties involved in the video call can have access to the chat.