The lensbling skull cap by blackrapid is a rear lens cap designed for nikon lenses this lens cap is made for lenses with a focal length that doesnt fall into blackrapids numbered line of caps when your lenses are in your camera bag its not always easy to tell which lens is which having the skull mark clearly printed on the rear lens cap will save you that brief moment of doubt as you reach to change lenses and could be the difference between getting your shot or not magic markers smear a