Plastic flag holder fits Catrike recumbent trikes and holds the flag securely in place while you ride. Allows easy mounting of a standard safety flag (not included). Works great on bikes with rack mounts on frame. Includes stainless mounting bolt. The inner diameter of the Catrike flag mount is 6mm and it works with 6mm flag pole shafts. Also, works on a Volae and may work on other brands of trikes, too.