A magnification of 20 power. Provided with eye guards. Each focusing knob is provided with a diopter scale that is graduated from -3 to +1 diopters in ½ inch diopter increments. Interpupillary distance of the eyepieces is controlled by an inter-ovular handle that is adjustable from 56 to 74 millimeters. An increase density control is provided to adjust the polarized light filters. Purge valves and an adjustable brow pad are provided for operator stability.