These 10 sets of D"Addario guitar strings have a micro-fine layer of EXP coating bonded to the 80/20 bronze-wrap wire, which is then wound onto a hex-shaped core wire. The result is a built-in barrier against the corrosion and wear that can quickly sap the life out of your guitar strings and your sound. EXP replacement strings have a natural round-wound feel and extra-bright tone that lasts three to four times longer than traditional guitar strings. Coupled with D"Addario"s compound-plated plain steels, EXPs are some of the longest-lasting, most natural-sounding coated guitar strings you can buy.Extra light gauges: 10-14-23-30-39-47.....