Got this cap for my Canon Prime lenses. I don't like the stock Canon cap because it's really hard to insert/remove when the hood is on the lens. I've tried the Tamron caps and they're alright ... but the Nikon caps just feel much more comfortable.
The only drawback is that now all my nice expensive Canon lenses have Nikon and Tamron lens caps. These caps confuse people who are looking at my Canon gear and wondering why I'm using Nikon gear or cheap 3rd party lenses.
I don't know why Canon can't figure out how to make a decent lens cap. Until they do, I highly recommend these Nikon caps. The quality is good and they're reasonably priced.