Used for: cutting off the content of a field at a certain length/number of characters.
For some export channels (e.g. Google Adwords or Marktplaats) certain fields (e.g. title) have a character limit. For example, let's say the character limit for the "title" field of an export channel is 30 characters. Using the "maximum length" rule we can cut off the title at 30 characters, making every title fit within the maximum length of the export channel.
You can choose to either cut off the title directly after 30 characters or to cut off the title after the last complete word that fits within the 30 character limit.
The effect of both rules is shown in the screenshot below.