National geographic 21mm25mm bk 7 binoculars national geographic 9024000 these 8 x 21mm binoculars from national geographic have been manufactured to a high standard complete with an attractive convenient design fully coated bk 7 optics and solid mechanics enable a true colour image reproduction the pocket binoculars include not only a diopter adjustment and foldable rubber eyecups for eyeglass wearers but also a handy pocket the full package includes binoculars bag caps and instruc