Fender 250 Nickel Plated Super Bullets Electric Guitar Strings. We matched the great tuning stability of our patented Bullet end with our Super 250s to create the ultimate strings for modern trem players. The German-machined Bullet end is designed to fit precisely in the tremolo block to ensure that the string returns to the same spot even after heavy tremolo use. The end of your tuning problems could be on the end of these strings! Fender Nickel Plated Strings, Great gutsy sound, bullet ends for Strats. Nickel plating is carefully applied to the steel cover wrap allowing geater volume and superior high end response.