The 7-element, Nagler Type 6 design is based on the original patented Nagler design. This new 7-element design update for the short focal length Nagler deserves its own designation. Using different exotic materials, coating processes and design ingenuity, Al has massaged more eye-relief, contrast, and true field of view into the shorter focal length Naglers, while maintaining the absolute sharpness of the originals. Eye-relief is 12mm on each model, and all are sized about the same as the original 7mm! Weight about 0.4 to 0.5 lbs. Available in 13mm, 11mm, 9mm, 7mm, 5mm, 3.5, and 2.5mm focal lengths.