Resistor for led lights, high quality and compact dimensions.Indispensable when all the direction indicators are replaced with LED lights and the acceleration is intermittent because the LED, having a much lower absorption than a traditional incandescent lamp, causes the relay to malfunction.This device must be installed in series with only one of the direction indicators at your choice, it is sold individually to give the possibility of replacement in case of failure but for a vehicle you have to buy a pair and install one for the right side and one for the left side.