5bd92e4f___Description
[Property] pixel [Type] String [Description] 
The URL address to an invisible tracking pixel. We use this pixel to calculate impressions and is required to be present in all adunits. Maximum length of this field is 36 characters. Note: The forward slashes in this field are escaped with backslashes to make it valid JSON. Backslashes should be removed via your favorite method before inserting into emails. Note: This is a unique, generated address and should not be reused multiple times.
Description