Summary: I purchased this to replace those cheap plastic covers the comes with my prime and kit lenses. Personally, I perfer the Tokina rear lens cap because it covers the ENTIRE lens mount. However, since it doesn't appear to be an item that's sold anywhere, the Nikon is the next best thing... I'm not convinced the 3rd party versions are as durable or snug. I'm actually a little upset that these don't come with every Nikon lens.
Summary: I bought a Tokina 11-16/f2.8 from B&H, great lens by the way. I didn't like the front lens cap so I replaced it with a Nikon 77mm lens cap. So at the same time I replaced the rear caps as well.