Martin Authentic Acoustic Lifespan 2.0 guitar strings are now offered in a convenient bulk box. This bulk box contains 25 sets and is packaged in an easy-to-use system designed for corrosion resistance. These strings are made from 92/8 phosphor bronze and feature a top-quality bronzed-steel core wire and bronze wrap wire. They provide a well-rounded sound that is clean and balanced, making them suitable for a wide variety of music styles. These acoustic guitar strings can be used for fingerpicking and flat-picking and are best for rigorous practice and performance. String gauge is an important part of getting the best sound out of your guitar. Martin recommends using their extra-light through medium-gauge strings on their guitars. Medium-gauge strings deliver more volume and are perfect for larger-bodied guitars. Enjoy incredible tone, no matter what you play.