These are strings for acoustic guitars and are professional acoustic guitar accessories with good sound transmission. Features: 1. The coating forms a protective shield between the strings and the environment, effectively extending the life of the strings. Reduces string rust caused by air and perspiration corrosion. 2. E-1st, B-2nd strings are nickel-plated steel wire smooth strings. G-3rd, D-4th, A-5th, E-6th strings are hexagonal steel core with coatedphosphor copper alloy wound strings. 3. The surface of the bead end is coated, which is stable and not easy to lose sound. It firmly locks the strings and transmits the timbre. 4. The strings have a pleasant sound, strong penetrating power and good sound transmission. The sound of the strings is pure, and the strings are wear-resistant and durable. 5. These strings are suitable for acoustic guitar use and are suitable for performance use. Note: 1. Due to manual measurement, the size may be slightly different. Thank you for your understanding. 2. Due to different light conditions and different monitors, item color displayed in photos may be showing slightly different from real object. Specifications: Model: SG108-011 ( Moderate Hardness )SG108-012 ( High Hardness ) --Optional Color: Silver + Gold Material: E-1st / B-2nd: Nickel-plated Steel Wire Smooth String, G-3rd / D-4th / A-5th / E-6th: Hexagonal Steel Core with CoatedPhosphor Copper Alloy Wound String Packing Size: 13*11*1cm / 5.12*4.33*0.39in Net Weight: 35g / 1.23oz Gross Weight: 53g / 1.76oz String:Diameter E-1st:0.30mm / 0.012inch B-2nd:0.40mm / 0.016inch G-3rd:0.61mm / 0.024inch D-4th:0.80mm / 0.031inch A-5th:1.03mm / 0.041inch E-6th:1.35mm / 0.053inch Package List: 6 * Guitar Strings