A Click-Tracker is always assigned to an AdSchedule. You need to store Link Ads in it, which basically consist of an ad name and a target URL. Furthermore, the information whether it is a click tracking, impression tracking and/or a background link ad is also put in here. Optionally, Link Ads (TXT Files) that have been uploaded to the Asset Library may also be added to the Link Ad of the Click-Tracker.

A Click-Tracker covers the whole runtime of the AdSchedule and thus of the Mercury plan item from which it came. Any number of Click-Trackers can be attached to an AdSchedule. 

Click-Trackers can be easily distinguished from AdSlots because they have a lock symbol on the right-hand side, whereas AdSlots have no symbol here.