A Contact Unit is a type of multi-purpose Culture spacecraft. A related development was the Contact Vehicle.
The smallest Contact Unit built by the 24th century CE was the Scree-class Limited Contact Unit. Relatively few were built; the Minds of the Scree-class were regarded as "guaranteed to go a bit mad" due to the extremely small crew size of five. By contrast, an Escarpment-class General Contact Unit of the late-20th century CE carried a crew of 300, and the GCU Grey Area of c. 19th century CE was designed for a crew of 300.
Contact Units were equipped with Contact procedures and equipment, which enhanced their information gathering capabilities. GCUs could perform a full scan of a planetary civilization within a few months, in addition to despatching Contact personnel for low-level reconnaissence.
The Troubadour-class, an early class of GCU, was in service by c. 6th century BCE. 
- Matter, chapter 13
- The Hydrogen Sonata, chapter 16
- The State of the Art, chapter 2.1
- Excession, chapter 9.7
- Use of Weapons, chapter 4
- "The State of the Art", chapter 2.3
- Consider Phlebas, The war, briefly
- Use of Weapons, chapter 1.Three
- Excession, chapter 2.2
- Consider Phlebas, chapter 1
- "The State of the Art", chapter 3.1
- "The State of the Art", chapter 7