From publisher blurb: One of the drop in resolution sub-systems for StarCluster 3, In Harm's Way: StarCluster, and Commonwealth Space. The StarZero Sub‐System uses 2d6 dice to play. All rolls are made with2 d6, and the Sub‐system uses the Starzero Character Sheet along with the Character Generation Worksheet. We recommend that the two dice be different in color, texture, size or marking. User note: freely available on the publisher website as a distinct file.