Country:  United States of America (USA)
Manufacturer / Brand:  National Airphone Corp.; New York (NY)
Year: 1925 Category: Broadcast Receiver - or past WW2 Tuner
Valves / Tubes 1:
Main principle TRF (Tuned-Radio-Frequency but use of regeneration unknown)
Power type and voltage Dry Batteries
Power out
from Model: Monodyne - National Airphone Corp.; New
Notes One dial (primary tuning control knob)
External source of data Ernst Erb
Source of data Radio Collector`s Guide 1921-1932
Mentioned in Guide to Old Radios

All listed radios etc. from National Airphone Corp.; New York (NY)
Here you find 15 models, 13 with images and 1 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.