The industry standard for over 40 years! Protects livestock and humans from induced voltage of overhead high voltage power lines. Eliminates induced 60Hz voltage from fences (including non-electric fences), metal buildings, irrigation pipes and other metal objects. Will not affect operation of standard electric fence chargers. Original design tested and approved by BPA (Bonneville Power Administration) 60Hz and 50Hz models available Includes mounting hardware for "T" type metal post Model 800900A Specifications Impedance of filter with a 60Hz RMS current level of: 1 milliampere <500 ohms 5 milliampere <500 ohms 10 milliampere <500 ohms Impedance of filter to a 10 volt RMA 500 Hz signal >10k ohms Impedance of filter to a 10 volt RMA 50,000 Hz signal >10k ohms Maximum RMA voltage input at 1000 Hz without break-down 1000 volts Nominal lightning arrester flashover rating 12,000 volts Insulation break-down rating 3000 volts RMS 500 Average life expectancy of filter: 15 years Size : 2-1/2" X 2-1/2" X 3-1/2" Weight : 1.75 lbs.