The Scree-class was a type of Culture Limited Contact Unit active by c. 19th century CE. Screes were very small; they were the least expensive type of Contact Unit to build. They were only 80 metres long; types of ancient Culture missiles were larger than them. Screes were nearly unarmed. The class only had a crew of five. This was regarded as far too small to maintain a healthy psychological state in the Mind. The custom-designed Type 5 Offensive Unit built by the GSV Sleeper Service in the decades prior to the encounter with the Excession near Esperi were based on a militarized Scree.