Martin MSP4200 Studio Performance Phos Bronze Acoustic Guitar Strings Medium .013 - .056star rating 5Steve GougeJanuary 28, 2010I have tried just about every acoustic string ever made and these are absolutely my favorite strings. I play a Santa Cruz OM/PW fingerstyle and love the deep, resonant lows and crisp, clear highs these strings produce. And they aren't as bright and twangy as the 80/20's. They are the only strings for me!