Special Features:

Installed in front of the pilot, attached to the structure above the windshield, can be tucked away when not inuse by releasing a catch and stowing it like a sunvisor in a car, the glass in transparent, but has a special coating that reflects the green image projected by the overhead unit, knobs on the allow the pilot to control the brightness and contrast of the images

Properties:

A piece of optically flat glass with associated mounting hardware which displays projected graphical data from the generator, symbol, head-up display in the operators field of view. this permits the operator to view the data while maintaining a normal head-up position and without obstructing normal field of vision. it is also used in what is known as display unit, head-down, found in helicopters and some aircraft.