The Yageo CFR series 180O is a carbon film resistor which is manufactured by coating a homogeneous film of pure carbon on high grade ceramic rods and after a helical groove has been cut in the resistive layer tinned connecting leads of electrolytic copper are welded to the endcaps where the resistor is coated with layers of tan colour lacquer.Insulation Resistance :in V-block for 60 Sec Temperature coefficient (ppm/°C): -500∼350Maximum Working Voltage:250V