3901 N. Mississippi Avenue
Portland, OR 97217
Lamp Size (shown in actual size)
Lamp size is determined by the maximum diameter expressed in eighths of an inch (1/8’). For example: an A19 lamp is 19-eighths of an inch or 2 3/8’ in diameter. To determine a lamp size, use the full size scale shown above (calibrated in eighths). Place one edge of the lamp to be identified on the top edge of the scale and measure the approximate diameter by reading the scale at the opposite edge of the lamp. Sizes of the more popular lamp types are indicated on the scale.
The size and shape of a bulb is designated by a letter code followed by a number. The letter indicates the shape of the bulb and the number indicates the diameter in eighths of an inch.