3 7/8" X 3 5/8" (99mm X 82mm)

(embossed inside base) WESTINGHOUSE

Picture courtesy Ben Kirsten

3 7/8" X 3 5/8" (99mm X 82mm) -- base view

(embossed inside base) WESTINGHOUSE

Picture courtesy Ben Kirsten

4" X 3 1/2" (101mm X 79mm)

(embossed around pinhole) THE MAYER & ENGLUND CO. PHILA U.S.A.

Picture courtesy Matt Grayson