Radio Operator's Information File KC-135 which told him how far

which told him how far he was from the point of touch-down

It included a toggle in the center to test that the bulbs were good

Type AN5780-3

This Cold War / Vietnam War era Radio Magnetic Indicator (RMI) ID 250/ARN was made by Bendix for use in aircraft of the US military in the 1950/60's and used in the AN/ARN-14 Radio Navigational System (see illustrations)

Radio Operator's Information File KC-135 which told him how farThis is an original WWII era Radio Operator's Information File published in 1944 (updated 1945) by the US Army Air Force. It is the basic reference book for aircraft radio operators in the performance of their duties. See photos. The page numbers are by section, so total pages are not estimated here. It is about 1 2 inch thick. All pages are intact as is the soft cover. It is in exceptional condition given its age.