Canon EW75II Lens Hood for Canon EF 20 f/2.8 & EF 20-35mm f/2.8L SLR Lens
A lens hood provides multiple functions: it shades the lens from stray light, improving your contrast and image quality; in inclement weather, it can assist in keeping moisture or wind-blown debris off the lens; and it protects the front barrel from the inevitable impacts against walls, door frames, and other real-life obstacles.Almost all EF and TS-E lenses have a Canon lens hood engineered specifically for it.