Nickel Rockers Big Core Medium. Thanks to Rene Martinez, GHS is proud to bring you the guitar tones that have defined music for the last 20 years. Rene worked as a guitar technician for some of the biggest names in the music industry, including Carlos Santana, Stevie Ray Vaughan, Eddie Brickwell, Clint Black, The Moody Blues, and Prince. As a musician he understood what the players wanted and in turn developed his own new products and techniques for them to use. Designed for maximum feel, balance and endurance, the wound strings are structured with a bigger core and nickel wrap of the highest quality - the plain strings are slightly bigger also, to best retain size and durability. Ideal for playing in your living room or on the world's biggest stages. Gauges: 011. 5-015-019-028-038-056