Designed to prevent stray light from entering the lens in order to keep unwanted glare from affecting your photographs protection from stray light avoid unwanted glare genuine canon accessory for ef 28 80mm f35 56 ii ef 28 90mm f4 56 iii ef s 18 55mm f35 56 ef s 18 55mm f35 56 is ii and ef s 18 55mm f35 56 usm lenses