Product Description XL Nickel are the industry standard in electric bass strings. With their clear fundamentals, booming tight lows, and reliable D’Addario construction, they’re trusted by players everywhere to handle any performance. XL Nickel bass strings are made with a high carbon steel core and wound with nickel-plated steel wrap wire, for consistently bright tone and smooth playability, great for a wide variety of bass styles. This 18-45 Regular Light set is a 12-string version of our most popular bass gauge, adding two octave strings for each of the standard four — E,A,D, and G. From the Manufacturer EXL170-12 is a 12-string version of the best-selling D’Addario bass set. With the addition of octave strings, this set offers the ideal combination of bright, booming tone and comfortable feel. The most versatile and universally appealing set for all playing styles. Fits long scale basses with a string scale length of up to 36 1/4 inches. D'Addario XL Nickel Wound Electric Bass strings are world-renowned as "The Player's Choice" amongst bass players of all genres and styles. All XL strings are precision wound on our exclusive digitally-controlled machines, ensuring each string has excellent intonation, clear fundamentals, and unparalleled consistency. Each string is wound with a nickelplated steel wrap wire known for distinctive bright tone with excellent magnetic output delivering a universally appealing and versatile tone for all playing styles.D'Addario, the world's largest manufacturer of musical instrument strings, is known as The Players Choice with a reputation for unsurpassed quality and consistency. D'Addario's innovative packaging reduces waste and provides protection from corrosion. All D'Addario strings are manufactured in the U.S.A. using proprietary, digitally controlled, state-of-the-art machinery for unmatched performance, set after set.