Overview: Lens hoods are primarily designed to avoid unwanted stray light from entering the lens by extending & 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. Dedicated lens hoods are designed to match the specific focal length of the lens it was designed for. Compatible Products:for CANON EF 85mm f/1.8 USM EF 100mm f/2 USM EF 135mm f/2.8 Soft focus EF 70-210mm f/3.5-4.5 USM EF 100-300mm f/4.5-5.6 USMSpecification:3.6 x 3.6 x 2.1