Base
The HB3 lamp uses either a P20d base in accord with IEC 60061.
Power and output
Under ECE Regulation 37, which governs automotive filament lamps in most of the world, the HB3 lamp's nominal rating is 60 watts at 12 volts, and its test rating is 68W (maximum) and 1550 ±15% lumens at 13.2V.
The United States government does not recognise ECE regulations, but rather applies its own regulations.
12-volt HB3 lamps are generally manufactured and tested to comply with both regulations.
Colour of light
Under ECE regulations, HB3 lamps are required to emit white or selective yellow light. U.S. regulations require HB3 lamps to emit white light. Under both ECE and U.S. specifications, the allowable range of white light is quite large; some HB3 lamps have a slight blue or yellow tint to the glass yet still produce light legally acceptable under the requirement for white light.