Not only does the DOT require a box of healthy 3 reflecting triangles but it is high safety precaution when being on the side of the road. Especially if it’s over a flat tire because you didn’t properly inflate it since you didn’t have a Legacy HGH2-FZ Truck Tire Inflator Kit 😉
Rather you just bought a truck, or yours have cracked I would suggest ordering these to your front door.
They are packaged in the rectangular red box in the picture. Easy fold, and unfold for your use.