Base
The H7 lamp uses a PX26D base in accord with IEC 60061.
Power and output
Under ECE Regulation 37, which governs automotive filament lamps in most of the world, the H7 lamp's nominal rating is 55 watts at 12 volts, and its test rating is 68W (maximum) and 1550 ±15% lumens at 13.2V. R37 also contains provisions for 6-volt, 55-watt and 24-volt, 70-watt H7 lamps.
The United States government does not recognise ECE regulations, but rather applies its own regulations.
Under these, the H7 is rated 65W (maximum) and 1410 lumens ±15% at 12.8V. Despite the two different sets of specified voltages and test protocols, the lamps themselves are the same; with few exceptions, 12-volt H7 lamps are generally manufactured and tested to comply with both regulations.
Colour of light
Under ECE regulations, H7 lamps are required to emit white or selective yellow light.U.S. regulations require H7 lamps to emit white light. Under both ECE and U.S. specifications, the allowable range of white light is quite large; some H7 lamps have a slight blue or yellow tint to the glass yet still produce light legally acceptable under the requirement for white light.