Nikon LF-4 Rear Lens Cap

This cap clicks on with a reassuringly solid feel, and the snug fit keeps dust off my expensive glass. It's a simple accessory, but the build quality is noticeably better than cheaper knockoffs I've tried.

Finally got around to checking the fit on my 50mm and it clicks into place with a satisfying, secure snap. Much better than the generic caps I was using before.

Fits my F-mount lens perfectly and clicks into place with a satisfying snap—the dust seal feels secure enough that I don't worry about scratches when swapping lenses.