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, 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.
The lens hood fits fine and secure. As another reviewer said the center pull lens cap also works well with this lens and I purchased one it does as he said it would. A good combination.
I was so happy to find this lens hood! I bought it for an out of date 105mm micro D lens and it is perfect! All I could find prior to this were used ones so I was thrilled when I looked here and it was the only place that had them brand new! thanks!