Ernie Ball Not Even Slinky electric guitar strings are ideal for lower tuning. Not Even Slinky are the optimal gauge combination for Drop D and Drop C tuning. The wound strings are a nickel-plated, steel wire wrapped around a hex-shaped steel core. The plain strings are made of tempered, tin-plated, high-carbon steel, for a well-balanced tone. All Ernie Ball strings are manufactured to the highest standards and the most exacting specs to assure consistency, optimum performance, and long life. Gauges: 12-16-24p-32-44-56.