Electric lamps, United States Government master specification for lamps, 1928 supplement to United States Government master specification for lamps, electric, incandescent, large, tungscen filament, Federal Specifications Board Specification 23b, revision promulgated Nov. 23, 1927, officially promulgated by Federal Specifications Board, Feb. 15, 1923, for use of Departments and independent establishments of Government in purchase of large tungsten filament incandescent electric lamps. 11th [edition].