Advanced performance H7 CANBUS LED resistors anti flick forward lightings/fog lights/DRL decoders are used for fixing the malfunction of H7 LED bulbs not light up or flickering on and off, or error code on the dashboard after installing the led bulbs for American and European vehicles due to the led bulbs draw much less current than stock lamps.
For most vehicles, LED bulbs just plug and play, easy installation. For some European or American vehicles, extra LED resistors or decoders or DRL anti-flickering harness maybe required to avoid the flickering or error code.