Upgrade your bass ukulele with the Aquila Thunderblack U•BASS Strings 4-String Set. Crafted from three unique synthetic elastomers, these strings deliver unparalleled volume and sustain. The third and fourth strings are enhanced with micronized metal iron powder, providing a sleek feel and stable intonation. Designed for musicians seeking superior performance, Thunderblack strings offer smaller diameters without sacrificing tension. Note: Not compatible with California & Solid Body U•BASS®. Elevate your sound with Aquila's innovative technology.