This little box is plug and play, if you have a 250 with drls you'll know that when the headlights are switched on the drls go off, this kit enables the headlights and the drls to be on together, it also dims the drls at night so they don't blind oncoming drivers. Never used, £70 posted anywhere in the UK, fitting instructions attached so you get an idea of how easy it is to fit, thanks Sent from my SM-G930F using Tapatalk
