Comes in Handy
Crutchfield Customer Review (What's this?)
Bold and Easy to use! Not cleverly designed to be an invisible lens cap.
Pros: My black Nikon lens-mount caps disappear in the jumble when my truck seat is full of gear. This one almost glows in the dark. When doing a lens switch and if it falls in the grass - IT DOES NOT DISAPPEAR like the black ones do. Also, Its heavy enough that it doesn't get blown away. Many times have chased and then hunted for those *%^\*! lightweight black ones after they spiraled away in the wind and rolled under rocks or plants. It's EASY to use because of the size and design.
Cons: Other than missing the fun I used to have spray painting my lens caps and lens-mount covers in bold colors - so I could find them when I fumbled and dropped one in the field (or into my gear bag) - can't think of a single thing I'd change.