Gauges 45-65-85-105. Rare phosphor bronze acoustic bass strings from DR Strings are a departure from the standard, good quality bronze string currently available, with a new, different, and stronger voice. You"ll notice a distinct improvement in the tone, depth, and sustain of your bass with Rare phosphor strings. Bass players who want a fatter, louder sound and a deeper bottom will appreciate the Rare phosphor tone, sound, and feel.