United States Army Signal Training School 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.
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.