Hi , these headphones were found in my parents attic . My MOM was a Sargent in the Army during WW2 and my uncle Bernie was in the Air Force . My Dad was , well , I can't tell you its a family secret to this day . From the little research I have done they might of been related to the Air Force , I really don't know for sure !!!!!  On the head band in orange paint  it has SC3975A . On the ear pieces it has ; MX-41/AR , RECEIVER ANB-H-1 , RADIO SPEAKERS INC.  , CHICAGO ILL.  , and F3  . I have no idea what all that means but their hard to see or take pictures of . I plugged them into my home stereo and they do work . Along with the headphones you will also receive the extension cord that was with them . The extension cord is a little over 4 feet long . " PLEASE " see the pictures because there's probably information I missed . Thanks , Stan .