The bracelets are cuff-style. They come in a number of colors and can be made of a number of materials: silver, stainless steel, aluminum, copper. They are engraved and go by many names, depending on their exact reason for being: memorial bracelets, KIA bracelets, POW/MIA bracelets, hero bracelets.
They have been used to commemorate police officers killed in the line of duty, victims of terrorist attacks, victims of domestic violence. But most of all, they are used to commemorate members of the military: those killed (KIA stands for “killed in action”), captured as prisoners of war (POW) or missing in action (MIA).