ATTP 3-21.9 describes how the Stryker Brigade Combat Team (SBCT) Infantry rifle platoons and squads fight. ATTP 3-21.9 discusses how they operate as Infantry, mounted in their Stryker Infantry carrier vehicles (ICVs), with the ICV in support, and as part of the Stryker rifle company. The content includes principles, tactics, techniques, procedures, terms, and symbols that apply to small-unit operations. ATTP 3-21.9 is intentionally designed as a companion manual to FM 3-21.8. Many of the subjects covered in FM 3-21.8 are not only mutually applicable to the Stryker platoons and squads but also nearly identical and need not be republished. Because of this, ATTP 3-21.9 focuses on the unique characteristics and capabilities of the Stryker platoons and squads. Major areas reduced, or not included in this manual, are covered in detail in FM 3-21.8 and include- -Dismounted tactical movement. -Employing fires. -Troop-leading procedures (TLP). -Sustainment. -Air defense. -Chemical, biological, radiological, and nuclear (CBRN) operations. -Composite risk management. -Fratricide avoidance. -Urban operations (UO). -Sniper operations. -Patrols. -Employment of the dismounted element's weapons. -Platoon and squad fire planning. -Air assault operations. -Defeating improvised explosive devices (IED). -Obstacle reduction and employment. -Dismounted fighting positions. These are basic skills that Stryker small units and their leaders must understand, practice, and execute. Their absence from ATTP 3-21.9 in no way diminishes their importance. Rather, they are fundamental skills applicable to all Infantry units and leaders. To fully understand operations of the SBCT Infantry platoons and squads, leaders should also study FM 3-21.11, FM 3-20.151, Infantry platoon tasks on the Digital Training Management System (accessible on Army Knowledge Online [AKO]), Soldier's Manual of Common Tasks, and other manuals listed in the references. ATTP 3-21.9 supersedes FM 3-21.9, published in December 2002. The contents of the older manual are based primarily on the SBCT concept paper and interviews conducted during visits to the first Stryker-equipped units as they organized at Fort Lewis. ATTP 3-21.9 includes changes based on operational experience of deployed SBCT units. It also incorporates information on current Infantry platoon and squad tactics, the employment of the ICV, and the integration of command and control (C2) systems during combat. The target audience for ATTP 3-21.9 comprises SBCT platoon and squad leaders, SBCT Soldiers, and those that desire an understanding of how they fight and operate. ATTP 3-21.9 applies to the Active Army, the Army National Guard/Army National Guard of the United States, and the United States Army Reserves unless otherwise stated. The proponent for this publication is the United States Army Training and Doctrine Command (TRADOC). The preparing agency is the U.S. Army Maneuver Center of Excellence (MCoE).