The IMAC Barlow TMK Surge Arrestor has non-linear voltage current characteristics and limits potentially destructive voltage levels without interfering with cathodic protection. Nominal values are 50 ohms at 250 volts – 30,000 ohms at 3 volts. It is self-healing and able to survive multiple strikes with your choice of wire size connections. Designed for above or below ground installation with fiber-glass housings available for above ground installation.