Magma Acoustic Guitar Strings Light + Gauge AMALGAM PB and SP wound Set, .011 - .052 (GA130SPB)ACOUSTIC GUITAR AND PHOSPHOR BRONZE WOUND AMALGAM STRINGS These unique acoustic guitar strings are wound with two special wires, phosphor bronze alloy and silver plated copper. This blend of materials perfectly combines to provide players with a great balance between warmth and brilliance. The mixture (combination) of these high quality materials brings the mellow tone of the Phosphor Bronze wound strings and the projection and volume of the Silver