OPUS Reader is a portable bus card reader that is compatible with OPUS cards and occasional cards. The app displays the current passes, the number of remaining tickets, and the history of past trips made with the card. However, it should be noted that the app is developed independently without the help of public transport networks, so the results are only indicative.

The application is compatible with the majority of transport networks using the OPUS technology, but some information is incomplete on certain networks. Additionally, the passes on occasional cards are not functional at the moment.

Overall, OPUS Reader is a useful tool for those who frequently use public transport and want to keep track of their passes and tickets. However, as some information may be incomplete and the app is not developed in collaboration with public transport networks, users should use it as a reference only.