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At GoodBulb, we strive to improve your lighting know-how. Through blogs, presentations and one-on-one consultations, GoodBulb aims to help you not only understand how lighting works, but how to chose the best bulbs for your lifestyle. We provide the knowledge to empower you to light your world.

Bases And Filament Types

Base and Filament Types

The code number of a filament consists of a letter or letters to indicate how the wire is coiled. A number followed by the letter indicates the arrangement of the filament on the supports. The letter “C” is commonly used indicating “Coil” type filament.

Bulb Shapes and Sizes

The code number of a bulb consists of a letter or letters followed by a number. The letter indicates the shape of the bulb and the number relates to the diameter of the bulb in eighths of an inch. The mosts commonly used household bulb is the A-19. The bulb is “A” type and the diameter would be 23/8″. A 65BR40 is a 65 watt reflector 5″ in diameter.