D'Addario Flat Tops acoustic guitar strings with a warm, semi-bright tone Extra Light Gauge - EFT15 Flat Tops Phosphor Bronze Semi-Flat Wound Three Polishing steps produce a smooth, semi-flat playing surface without sacrificing the tone and sustain associated with phosphor bronze strings. Flat Top's smooth feel reduces surface friction and finger noise, making them ideal for recording and slide guitar. gauges: E-.10, B-.14, G-.23, D-.30, A-.39, E-.47 (inch)