United States Army 3rd Chemical Brigade Class A Patch
Criteria: Class A Patches, known broadly as shoulder sleeve insignia (SSI), are embroidered patches used by major formations of the United States Army. Each formation has a unique formation patch, and the U.S. Army is unique among the Armed Services in that all soldiers are required to wear the patch of their headquarters as part of their military uniforms.
Shoulder sleeve insignia are most commonly worn on the upper left shoulders of all U.S. Army uniforms, though they can be placed on other locations, such as a combat helmet. Shoulder sleeve insignia worn on the upper right shoulders on Army uniforms denote former wartime service. These "combat patches" will not be worn on the new Army service uniform. Instead a 2-inch metal replica will be worn on the right breast pocket and is officially known as the Combat Service Identification Badge.
Full color SSI are only worn on the Service Green Uniform. Formerly, full color SSI were also worn on the "full color" (white letters on black or dark blue material) Military Police brassard, worn by MPs while wearing the green "Class A" service uniform or while wearing subdued field uniforms (BDU or DCU) in a garrison environment.