The NYXL Nickel Wound Medium guitar strings come in gauges 11-49. This is a pack of 5 and comes with a free NS Micro Headstock Tuner. D Addario NYXL guitar strings will bend farther sing louder and stay in tune better than most other strings. Envisioned perfected and manufactured by D Addario in New York the break-resistant high-carbon steel core and plain steel alloy delivers a whole new level of freedom confidence and power. NYXL s provide more strength and 131% more tuning stability by utilizing a completely reinvented wire drawing process and revolutionary corrosion-resistant tin coating application. The reformulated nickel-plated string windings have greater magnetic properties resulting in higher output and enhanced mid-range frequency response for more presence and crunch. The NYXL0942 set is designed for maximum flexibility. NS Micro Headstock Tuner The NS Micro offers improved accuracy faster response expanded calibration range visual metronome mode and an improved ratchet design. A highly sensitive piezo transducer and easy-to-read multi-color backlit display allow smooth and highly accurate tuning in noisy dim or well-lit environments while the micro design and reversible screen allow the tuner to hide effortlessly behind or mount on the front side of the headstock allowing the tuner to remain clamped to the instrument inside most cases when stored. A 360-degree swivel mechanism and adjustable padded clamp offer optimal viewing angles and maximum positioning flexibility. As a result the NS Micro is equally at home on left- and right-handed instruments as well as on small and large headstocks making it an ideal choice for the widest variety of players and instruments. The NS Micro is powered by a readily available CR2032 battery (included) and provides maximum battery life utilizing an auto-off function shutting the tuner off automatically after several minutes from power up.