A real gem of the Nikon close-up photography system is the Bellows Focusing Attachment PB-6 -- a superbly crafted unit you'll delight in using. A twist of the knob lets you vary the lens extension at will, producing frame-filling images of the most minute subjects. Provides continuously variable extension from 48mm to 208mm. An Auto Extension Ring is required when the PB-6 is used with the F5, D2H or D1 series. The PB-6 cannot be used with G-type Nikkor lenses.