Identify Your Bulb

Bulb type can be identified via examining several elements: filament, base and shape. Here is some information and pictures to help to identify your bulb.


Bulb Shapes (Not Actual Sizes)
The size and shape of a bulb is designated by a letter or letters followed by a number. The letter indicates the shape of the bulb while the number indicates the diameter of the bulb in eighths of an inch. For example, "T-10" indicates a tubular shaped bulb having a diameter of 10/8 or 11/4 inches. The following illustrations show some of the more popular bulb shapes and sizes.

Bulb Shapes
Bulb ShapesPAR bulbs - product pages 2 to 5
Bulb Shapes


High Intensity Discharge

High Intensity Discharge
High Intensity Discharge


Fluorescent Lamps

Base Types (Not Actual Sizes)

Fluorescent Lamps Base Types

Bulb Shapes (Not Actual Sizes)
The size and shape of a bulb is designated by a letter or letters followed by a number. The letter indicates the diameter of the bulb in eighths of an inch. For example, "T-12" indicates a tubular shaped bulb having a diameter of 12/8 or 11/2 inches. The following illustrations show some of the more popular bulb shapes and sizes.

Fluorescent Lamps Shapes and Sizes Fluorescent Lamps Bases

Filament Designations
Filament Designations consist of a letter or letters to indicate how the wire is coiled, and an arbitrary number sometimes followed by a letter indicate the arrangement of the filament on the supports. Prefix letters include C (coil) - wire is wound into a helical coil or it may be deeply fluted; CC (coiled coil) - wire is wound into a helical coil and this coiled wire again wound into a helical coil. Some of the more commonly used types of filament arrangements are illustrated below:

Filament types


Base Types (Not Actual Sizes)

Base Types


If you still cannot identify your bulb type email us at info@lightbulbplace.com.

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