ATTP 3-21.9, "SBCT Infantry Rifle Platoon and Squad," 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.