The Olympus LH-61C Lens Hood is a replacement lens hood for the Olympus Zuiko 14-42mm f/3.5-5.6 zoom lens, as well as their M.Zuiko 14-150mm f/4.0-5.6 lens.
Lens hoods are 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, one also gets the added benefit of some extra protection from accidental impact.