The Canon ET-54 Lens Hood, as with other lens hoods, is made to keep undesired side lighting from entering the lens. It does this by extending and shading the end of the lens. Furthermore, since the since the hood extends from the lens, it gives extra protection from accidental impact. It is removable and attachable in reverse to take up as little space as possible when storing in camera bag.
The Canon Lens Hood ET-54 is compatible with the EF 55-200mm and EF 80-200mm Zoom Lenses.