Most content filter solutions rely on file types, a few use some type of image analytics to check for skin tones to try and classify offensive images but only the Firstwave solutions scans all attachments and classifies them as non business or offensive.
Firstwave have a unique system that allows you to see and control the content coming and going via email. Giving you Visibility into the content by showing thumbnails of the actual attachments so you can gauge if the content is acceptable for your organisations culture.
Seeing the attachments gives a very different perspective on what content is actually in your email flow. You decide the actions to take and the Firstwave system does the rest.