The model features a split-apart chest plate that opens to reveal internal organs (represented by a brown hood and red pieces).
If you are referring to the set (often associated with digital archives or reviews like "10186.rar"), it is a 1,085-piece Ultimate Collector Series (UCS) model released in 2008. Overall Consensus
It includes a solid, rotating stand with a custom information plaque. Pros and Cons LEGO Star Wars 10186 GENERAL GRIEVOUS Review! (2008)