Electrolytic-Tough-Pitch-(ETP) is the most common copper. It is universal for electrical applications. ETP has a minimum conductivity
rating of 100% IACS and is required to be 99.9% pure. It has 0.02% to 0.04% oxygen content (typical).
Deoxidized-High-Phosphorus-(DHP)is commercially pure copper, which has been deoxidized with phosphorus, leaving relatively high
residual phosphorus content. Copper alloy 122 is not susceptible to hydrogen embrittlement, but has relatively low electrical
conductivity due to the amount of phosphorous content.