What is best ac power cord ？

What is best ac power cord : 

For example, we use pure copper for all our Cat5 cables. Some competitors use CCA (copper clad aluminum or copper clad alloy) because it costs less. However, we believe pure copper is better because:

Bare copper is a more efficient electrical conductor than CCA.

CCA cables need heavier gauge (larger) wire to achieve the same Cat5e cable rating (350 MHz).

Bare copper is more durable, making it more resilient to jerks and pulls when the cable is going through tight corners and around sharp edges.

Bare copper causes less electrical loss, which is important when cables are run over long distances.

To properly carry a UL listing for Cat cable, it has to be pure copper.