Is the H4 bulb a combined high/low beam unit?

[LeVivian]

H4 bulb is a combined high/low beam unit. The H4 automotive bulb contains two filaments inside, one for the high beam and one for the low beam. Precautions for using high and low beams are as follows: Usage of low beam: When driving at dusk when it's getting dark or at dawn when light is just appearing, you must turn on the low beam; in fog, snow, or heavy rain when visibility is obstructed, you must turn on the low beam even during the day; when driving at night on roads with lighting but insufficient brightness, you should turn on the low beam. Usage of high beam: When meeting oncoming vehicles on roads without central barriers or center lines, you cannot use the high beam within 150 meters of the opposite vehicle; when meeting non-motor vehicles on narrow bridges or roads without central barriers or center lines, you cannot use the high beam; when passing through signal-controlled intersections, you cannot use the high beam while turning.