Ernie Ball Paradigm Acoustic Guitar Strings Are Amazingly Resistant To Rust And Breakage — And Whether You Earn A Living With Your Guitar Or Not, That's A Big Deal. These Phosphor Bronze Strings Deliver Vivid Tone Along With Advanced Engineering That Can Withstand Aggressive Players. And Even If You Travel With Your Guitar Often Or Live In A Salty-Aired Coastal Region, Paradigm Strings Will Stay Rust-Free For A Very Long Time.