Martin M550 Medium Phosphor Bronze Acoustic Guitar Strings Standard April 20, 2011/in All About Guitars /by sheetmusic$4.99 New Excellent sound and longevity with a silky feel.Martin M550 Medium Phosphor Bronze Acoustic Guitar Strings Standard http://www.sheetmusicdaily.com/wp-content/uploads/SheetMusicDaily-300x53.jpg 0 0 sheetmusic http://www.sheetmusicdaily.com/wp-content/uploads/SheetMusicDaily-300x53.jpg sheetmusic2011-04-20 12:03:312011-04-20 12:03:31Martin M550 Medium Phosphor Bronze Acoustic Guitar Strings Standard