EJS60, based on the gauges of the highly popular J60 set, offers light playing tension for comfortable playing feel and brilliant tone. Stainless steel construction provides a bright tone, smooth feel and long life. Loopend construction for universal fit. 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.