This canon lens 72mm hood is compatible with EF 28-200mm f/3.5-5.6 USM and EF-S 18-200mm f/3.5-5.6 IS. This canon lens hood is designed to prevent it from any unwanterd stray light to enter the lens by extending and shading the end of the lens. As the end of the lens is extended thus it have the benefit of extra protection in case of any accident. The hood of the lens contains petal shape which will maximize the hood coverage while putting the less possible weight. This dedicated hood is manufactured for specific focal length of the lens it was designed for.