BASS STRING SET XL Series Round Wound Bright Bass Strings, Regular Light, Long Scale (045 - 065 - 080 - 100). D'Addario XL Nickel bass strings are renowned worldwide as '' The Bassist's Choice '' whatever style it plays. XL strings are wound with great precision with nickel-plated steel onto a hex-shaped core, resulting in strings with a distinctive, shiny tone and excellent intonation.The nickel-plated steel wire wound around the core is known for its distinctive tone. brilliant and the excellent tuning it offers for all styles.