Abstract: Let F be a p-adic field. We consider representations of Arthur type of a classical group G over F. By use of the Endoscopic Classification, Moeglin gave an explicit way to construct Arthur packets when G is a symplectic or special orthogonal group. Further analysis by Xu and Atobe developed the notion of Extended Multi-Segments, which parametrise certain Arthur packets. We review the definition, the construction of these representations in terms of Langlands data and consider some combinatorial problems that arise in this context.