COATED CLASSICAL NYLON GUITAR STRINGS NORMAL TENSION: .028N .032N .040N .028W .035W .044W They don't call them "The Player's Choice" for nothing! D'Addario is the world's largest manufacturer of strings for musical instruments. Many top guitarists won't play any other brand. Pro-Arte strings are D'Addario's premium classical guitar strings. The wound strings are normally made from silver plated copper wound on nylon. However, the EXP Coated Pro-Arte's employ corrosion resistant EXP coated copper wire wound around a composite core. This gives an already long-lasting composite wire core an even longer life by virtue of the EXP coating. The silver plating is eliminated and the strings have an attractive copper hue. Rest assured that the EXP's will last much longer than standard wound strings. The EXP45's are a normal tension set with clear trebles and require the traditional classical guitar tie-on method at the bridge to restring your guitar. The environmental packaging reduces waste. And each set is sealed in a Corrosion Intercept bag for freshness. DA-EXP45$11.91 String Coatings for Longer String Life