Hi Howard - this is probably an overkill answer to your question but since you asked: Oxygen free copper (OFHC - oxygen free high conductivity) is a copper alloy that is produced by remelting electrorefined cathode copper (ETP) and casting it under a reducing atmosphere of carbon monoxide and nitrogen so that oxygen does not enter the copper and form a Cu2O phase. The Cu2O phase (which is present in ETP copper) reduces a copper alloy's electrical conductivity. OFHC copper is preferred for many electronic applications because of this improved electrical conductivity. Also, OFHC copper is typically free of gas porosity and hydrogen embrittlement problems that can be found in ETP copper. But - OFHC copper is more expensive than ETP copper due to the additional processing required to produce the alloy! Hope that helps. Dave Hillman Rockwell Collins [log in to unmask] Howard Lin <[log in to unmask]> on 02/09/99 10:47:38 PM Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to [log in to unmask] To: [log in to unmask] cc: Subject: [TN]