COPPER

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).
Typical Uses
Electrical engineering
Busbars, Conductors
Coaxial Cables
Transistor Components

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.
Typical Uses
Roofing
Gaskets
Auto radiators