Mus Las40 is a free Android game app developed by Las40. It is a web-based application that allows users to play the popular Spanish card game, Mus, in pairs against other online users. The game is played in two rounds, and after each round, there is an individual ranking update based on the players' results.

The app allows you to find a regular game partner to play in championships and climb up the ranking ladder as a team. It also offers free registration for periodic Mus championships, where you can compete with other players and improve your multiplayer ranking. Enjoy playing this classic card game in a fun and interactive platform with Mus Las40.