Specification Body - Binocular. Eyepiece - 15x wide field inclined at 45 degrees. Magnification: 21x to 135x, maximum 180x with optional 20x eyepieces. Working distance - 84 mm. Interpupillary distance - 50 mm. up to 74mm. Dioptre adjustment - +5.6D-7.2D on both eyepieces. Optical system - Greenough.