This application, as the name suggest, works like an overlay for Client of a popular game League of Legends. Before each round of a game, all players must enter an avatar or hero selection screen called Champion Select. Players collect certain points for playing each hero which is represented by Champion Level. Players can also get rewards if the reward is available on a certain hero. That information was not natively displayed in League Client up until version 12.23.1 and left players to remember or write that information down. This application solved those problems by displaying the requested data on top of League Client. League Client with overlay system is shown in the picture below. Numbers and chest icons near the champion icons are the result of this application. In addition to reward availability this application shows the hero mastery level and progression in that level.
The latest version release notes are available here.
This application can be download from here.
If you need any help with setting this up there is a setup page for additional information and setup steps.
New features from version 2.0 are described here in more detail.
If you want to update from version 2 you can follow the guide steps described here at the end titled Manual update.
Visit Wiki page for additional info.