This bundle includes three packs of Martin MA150S Authentic Acoustic Marquis Silked 80/20 Bronze Medium 13-56 strings. Martin Guitar knows a thing or two about pampering valuable instruments. If youâ€re looking for some extra protection for your fne guitar, Authentic Acoustic Silked strings are the right choice for you. Weâ€ve adding a soft silk wrap to the ball ends of our Authentic Acoustic strings to prevent wear and tear on the bridge and bridge plate as you play. Our silk wrap puts a comforting layer of protection in place every time you change your strings. Available in 80/20 Bronze and 92/8 Phosphor Bronze.Martin Authentic Acoustic Marquis Silked strings offer thread wrapping for bridge protection, corrosion resistance and excellent tuning stability.