Strings custom designed by EHX and made in the USA. Medium string tension (11-48). The smooth strings are made of high carbon round steel. Wound strings are round nickel-plated steel precision wrapped in a hexagonal-shaped high-carbon steel wire. Nickel-plated steel provides optimal magnetism for use with electric guitar pickups, plus a comfortable, smooth feel. The quality of the steel, the precision of the string and core diameters, and the high-tech, computer-controlled winding process result in strings that play better and stay in tune longer.