Prewar general coverage receiver with separate ham bands. This is National's 1940 "Silver Anniversary"model as stated on the diamond-shaped "NC" logo at the top center. Has rack-and-pinion band change. Pulling on the large tuning knob engages its pinion on a rack attached to a cast aluminum sliding coil tray to change bands.
Switch on lower right is a mod. The NC-2-40C and D are very similar post-war receivers with an audio input phone jack at that lower right location.
Early in WW II, in an informative ad in the February 1942 QST magazine, page 51, National noted that the NC-200 could, in an emergency, be operated on battery power with good performance from as little as 90 volts DC and, of course, a 6 volt storage battery for the filament supply. At 90 volts B+, the current draw with output tubes in place (speaker output) was 30 mA. With the output tubes removed and using headphones, current draw was only 10 mA. Current draw for higher voltages are also noted.