d’addario phosphor bronze acoustic guitar strings are acclaimed worldwide for their great, long-lasting tone. phosphor bronze was introduced to string making by d’addario in 1974 and has become synonymous with warm acoustic tone. diametertension item# noteinches mmlbs kg pl013 e0.013 0.3327.4 12.43 pl017 b0.017 0.4326.3 11.93 pb026 g0.026 0.6635.3 16.01 pb035 d0.035 0.8936.8 16.69 pb045 a0.045 1.1434.0 15.42 pb056 e0.056 1.4229.0 13.15