The D'Addario EJ19 set of guitar strings are hybrid gauge, combining the medium gauge bottom strings for increased resonance and volume with light gauge top strings for more comfortable playability and single note bending. A popular choice for bluegrass pickers but suitable for many genres.Phosphor Bronze was introduced to string making by D'Addario in 1974 and has become synonymous with warm, bright, and well balanced acoustic tone. D'Addario Phosphor Bronze strings are precision wound with corrosion resistant phosphor bronze onto a carefully drawn, hexagonally shaped, high carbon steel core. The result is long lasting, bright sounding tone with excellent intonation.D'Addario EJ19 Features:Preferred for its warm, bright, and well balanced acoustic toneEnvironmentally friendly, corrosion-resistant packaging for strings that are always freshMade in the U.S.A. for the highest quality and performanceString Gauges:Plain Steel .012, .016Phosphor Bronze Wound .025, .035, .045, .056D'Addario EJ19 Tensions:E:Item #: PL012Diameter: 0.0120" (0.3000 mm)Tension: 23.360 lbs (10.600 kg)B:Item #: PL016Diameter: 0.0160" (0.4060 mm)Tension: 23.310 lbs (10.570 kg)G:Item #: PB025Diameter: 0.0250" (0.6350 mm)Tension: 32.810 lbs (14.880 mm)D:Item #: PB035Diameter: 0.0350" (0.8890 mm)Tension: 35.870 lbs (16.270 mm)A:Item #: PB045Diameter: 0.0450" (1.1430 mm)Tension: 32.770 lbs (14.860 kg)E:Item #: PB056Diameter: 0.0560" (1.4224 mm)Tension: 27.750 lbs (12.590 kg) D`Addario EJ19 Phosphor Bronze Bluegrass Acoustic Guitar Strings, .012-.056.