Unicall, developed by Korea MutalTech Inc., is a free Android application that enables users to make international video calls and chats without requiring any personal information or roaming. The app also offers three-way calls and video lectures. It is an excellent tool for overseas travel and can be used with the Tour World app to obtain free local travel information.

The app also provides a contact service through Unicall, which is useful for consulting with tour planners. Duo, an innovative communication feature, enables voice calls and chatting simultaneously. Users can have 1:1 chat as well as group chat, with open and closed types for group chat. In the closed type, only the creator can add members. The app also allows users to make friends in various ways and provides a versatile calculator.

Overall, Unicall is an incredible app that provides free international video calls and chats, making it an excellent choice for people who want to stay in touch with their friends and family while traveling abroad.