Lens hood is primarily 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 some extra protection from accidental impact. 
It will fit for all 77mm filter size lens. 

Specification

Thread (Inner Diameter): 77mm
Made of metal
Color: Black
Compatible with: all cameras with 77mm filter size lens

Front diameter: 82mm; Height: 36mm