The Canon Lens Hood EW-88C is for the Canon EF 24-70mm f/2.8L II USM Lens. The EW-88C, 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.