T-2 1/4 Miniature Bulbs range in voltage between twelve (12) and twenty four (24) volts. The letter T in the designation T-2 1/4 denotes that the
bulb is TUBULAR shaped and that the glass envelope has a Maximum Outer
Diameter (M.O.D.) of two and one quarter eighths (9/32) of an inch or 0.28125" inches which is 7.14375 millimeters. All bulbs in the T-2 1/4 have one of the following filament designs: C-2R, C-8, C-6, CC-6 or a C-2V Filament Design.