The T designates that the bulb is tubular in shape. The number(s) following the T indicates the width of the glass envelope (not the base) in eighths of an inch. T3-1/4 Glass Wedge Base bulbs are three and one quarter eighths of an inch or 0.4063″ or 10.3188 millimeters in diameter.

What does T3 mean on a light bulb?

The T designates that the bulb is tubular in shape. The number(s) following the T indicates the width of the glass envelope (not the base) in eighths of an inch. T3-1/4 Glass Wedge Base bulbs are three and one quarter eighths of an inch or 0.4063″ or 10.3188 millimeters in diameter.

Do T3 bulbs come in LED?

T3 LED Bulbs(8 products)