The Bosch 1AB003177001 is a genuine H4 headlight insert designed for universal application in 12V and 24V electrical systems. This 178mm (7-inch) diameter headlight insert features both high beam and low beam functions, making it suitable for a wide range of agricultural machinery, commercial vehicles, and older vehicle models. It is ECE approved (E1 126, E1 127) and built with a durable glass lens and plastic housing for reliable performance. The H4 bulb is not included.