Callout extensions are manual AdWords ad extensions that show text below your text ad that is not clickable and therefore directs traffic to the same landing page in your ad or associated with the keyword. The cost per click is the same; there is no additional fee. Callout extensions are ideal for information to encourage consumers to choose your ad. This includes Free Shipping, Customer Support, 100% Satisfaction Guaranteed, and so on. You have up to 25 characters of space to utilize.
Sitelink extensions are another kind of AdWords extension, that can help encourage traffic to additional pages. Learn more about them in our post on Sitelinks.