The MA130S Silk and Steel strings are the right choice for you. Martin Authentic Acoustic Marquis Silked strings offer thread wrapping for bridge protection, corrosion resistance and excellent tuning stability. Martin Guitar knows a thing or two about pampering valuable instruments. Martin added a soft silk wrap to the ball ends of their Authentic Acoustic strings to prevent wear and tear on the bridge and bridge plate as you play. Martin's silk wrap puts a comforting layer of protection in place every time you change your strings