General Electric Foot-Candles Exposure Light Meter From The 1930s

2.5" Tall x 2.25" wide x 1.25" Depth

Manufactured by General Electric 

Model # 8DW40Y2

This was used by architects, lighting engineers, and factory inspectors to ensure office environments and work areas had adequate lighting levels.

This measures in Lumens/Sq. Ft. and is more than likely made around 1935.