Simplified Quick Action Tactics System: Modern Combat Manual - Core Rulebook

From the introduction: What is SQuATS? Squats is a simplified version of Ops and Tactics. It is designed with a very fast, exaggerated play in mind. Due to its cut down nature, it is completely incompatible with any Ops and Tactics Supplemental Material, and should be used as a standalone book for games where combat is the main focus, or for games where Ops and Tactics is not needed. When moving over from the Simplified Quick Action Tactics System to Ops and Tactics, be sure to re-read any of the options, as the values for many rules have been changed.