Fender Pure Nickel Bullet End 3150XL Xtra-Lite 9-40. Gauges 9, 11, 15, 24, 32, 40. Original Bullets: Pure Nickel Bullet End [3150s] Fender started with their pure nickel wound strings (Original 150s) and added their newly improved patented Bulletend. Designed especially for your tremolo-equipped electric guitar, the Bullet end lends additional tuningstability to the warm full vintage sound of pure nickel. Bulletsthe Strings for Strat guitars! Fender Model 073-3150-002