The all-new Martin SP Lifespan acoustic guitar strings are treated with Cleartone proprietary technology to bring you the longest possible string life without sacrificing tone or natural feel. Martin SP Lifespan strings are designed to repel the oils and dirt that can deaden strings. All six strings are treated to preserve the natural Martin SP sound and feel that players prefer. Many players delay changing strings. We put up with dead strings to avoid the task. Coatings that extend the life of the string may change the tone and feel of the string to the point of making it a compromise - long life or natural tone. The ultra-thin treatment repels dirt and grime that deadens strings and there's no flaking and no loss of treatment due to playing. The tone out of the box was natural and bright. String up with SP strings so you can stay in tune longer and play with confidence. Martin's SP Lifespan acoustic guitar strings start with the ulta-pure steel SP core wire giving you a perfect combination of tensile strength and response. They then add bronze electroplating to protect and enhance the core wire. The wraps are a perfect combination of metals to give you the warmth or brilliance you demand. Manufactured in their own facility, Martin SP acoustic guitar strings are crafted for tone and performance. From traditional brass ferrules to engineered lock twists, their raw materials and high quality standards deliver Superior Performance!