From Manufacturer
This large black LensCoat TravelHood is designed for 400mm f/2.8, 600mm f/4, and 800mm f/5.6 lenses as a lightweight and portable alternative to a standard lens hood. Its ribbed design allows it to wrap around the lens and fold flat to pack into your bag. Made from water-resistant material, the TravelHood can be used in inclement weather, protecting your lens from the elements, scratches, and lens flare. An anti-slip interior lining and hook-and-loop straps keep the TravelHood in place.