Classic Nickel Wound Slinky strings consist of pure nickel steel wrapped around a tin plated high carbon steel core for a warm rich tone that compliments many playing styles including jazz, rock and blues. Each set is packaged in an ultra low humidity environment with Ernie Ball's element shield packaging to ensure every set is as fresh as the day it was made • Precision wound with pure nickel steel. • High carbon steel hex core • Crafted in Southern California, USA. featuring the finest and freshest materials