The armband
The Romulan Rebirth movement was a paramilitary organization of Romulans with racist tendencies who claimed to be striving for the revival of their culture in the aftermath of the Romulan supernova. Members were identified by an armband worn on the left arm, and carried swords and disruptors.
In 2399, the planet Vashti in the Qiris sector of the Beta Quadrant was described by former Starfleet officer Raffi Musiker as a "hotbed" of this movement. The former senator Tenqem Adrev was a member of the movement in that year. (PIC: "Absolute Candor")