Canon ES-52 Lens Hood for 40m EF f/2.8 STM Lens
The Canon ES-52 Lens Hood for EF 40mm f/2.8 STM Pancake Lens is designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. In addition, since the end of the lens is extended, you also get the added benefit of extra protection from accidental impact.