I think we've all seen them. They are required on farm tractors and any vehicle that can not maintain the speed of the other traffic.
There is also one made for recumbents. It is not the hard aluminum ones you find for farm tractors. And some are a differant color pattern. Instead of the red & orange one style for 'bents is yellow & orange. And of course they are ot as large as the type for farm equipment.
The one I have attaches to my Vision Day Bag, it attaches with 2 velcro loops to the bags "handle" and just hangs there. I just bought it & have not ridden on the street with it yet. So I don't know if it will make a differance.
Anyone else use one of these? Did it help?