From the manufacturer:
”Our Medium gauge set is the go-to string for players who want a big, warm, beefy tone out of their guitar that will project with plenty of volume and definition. Pair that with the powerful low end of our Naturals, and you’ve basically wrapped yourself up in a blanket of tone so warm you could sleep outside in the Alaskan wilderness in the middle of winter. Take that hypothermia!
Naturals are our take on Phosphor Bronze, which is great at bringing out the the authentic, woody characteristics of an acoustic guitar. It’s this rich copper alloy that gives these strings a distinctly warm, resonant tone. The strings also have a rose gold color so beautiful you’ll want to order an extra set just to frame and hang on the wall.
As an added bonus, component agents in this alloy make these strings especially resistant to corrosion, meaning your strings will sound better, longer. Who wouldn’t like that?”