The 4 line filter has been designed to be chassis mounted and provide a feed through of up to 4 power or data lines. The filter is made of aluminium and the filter is encapsulated in polyurethane to ensure shock and vibration is contained. The input is via a mil std circular connector to provide a screened connection through the filter. The filtration performance of the filter has been tuned to provide the best for use with DC applications and air conditioning. The filter has 3 separate chambers to provide a high attenuation at high frequencies.