Each campaign has a budget and the capping is one of the tools of controlling it. It means that each publisher will have, as starting to promote that campaign, a daily budget as well, which is called capping.
The capping is measured in monetary terms, in our case Dollars, and not necessary installs.
You will find the capping for a campaign in the description page:
Every campaign, on its' description page, will have the information about the capping and it will always be displayed to the right of the Campaigns' title.
As the example above shows, for this campaign each publisher will have capping of $300 daily.
In this example, the CPI for Canada is $0.6, therefore the capping for this campaign in Canada is equivalent to 500 installs.
In order to increase your daily cap, you first need to deliver enough traffic to reach the current cap.
Once you reach it, you can contact your account manager to check the availability of a higher daily cap.