The Body Cap for Nikon F Mount Cameras from Sensei is a spare or replacement body cap for Nikon F mount camera bodies. It is a black plastic cap that twists onto the lens mount of the camera body. A body cap protects the camera's sensor and interior from dust and damage when a lens is not in place. Finger-grip edges on the body cap aid in placement and removal. Having an extra body cap is a good idea in case the original gets lost on vacation or assignment.