Airspeed / Mach Speed Indicator, US Air Force Type ME-4 F-101 Voodoo “Radio Set AN/ APN-2 is

“Radio Set AN/ APN-2 is an airborne radar interrogator / responder of the "Rebecca" type that will enable an aircraft to home on ground radar beacons of the "Eureka" type such as AN/PPN-1 and AN/PPN-2 and the heavier beacons

The switch rotates to each position on the dial

This is a fine example of a Cold War-era

but I'm leaving that to the buyer

Here is an Air Navigation Computer as used by US Air Force navigators from 1940-~1980 for dead reckoning navigation

Airspeed / Mach Speed Indicator, US Air Force Type ME-4 F-101 Voodoo “Radio Set AN/ APN-2 isThis is a Type ME 4 Air Speed Mach Speed Indicator with Maximum Allowable Indicator as used in the Cold War and Viet Nam War era's US Air Force Fighters F 100 Super Sabre and the F101 Voodoo. See images from their flight manuals. The indicator displayed airspeed from 60 850 knots, and mach speed from 0. 5 to 2. 2 mach. The knob, when rotated, adjusted the air speed index pointer along the perimeter of the airspeed scale. The red maximum airspeed