plastic. 13-pin.1 = Left indicator (yellow)2 = Rear fog light (blue)3 = Earth for power supply 1-8 (white)4 = Right indicator (green)5 = Right rear light, number plate, pos. light, marker lamp (brown)6 = Brake light (red)7 = Left rear light, number plate, pos. light, marker lamp (black)8 = Reverse light (pink)9 = Power supply, battery positive (Orange)10 = Charging current for battery in caravan (grey)11 = Spare (white/black)12 = Spare13 = Earth for power supply 9-12 (white/red)Pin 1-8 with 1.5 mm² cable. Pin 9-13 with 2.5 mm² cable.