Copper wound natural gut E string for double bass , providing rich detailed tone for discerning musicians . Gut strings are normally of a heavier gauge than steel equivalents , and nut , bridge and tailpiece may need to be modified to accept the thicker diameter string . All contact points should be smooth and lubricated with graphite to avoid damage to the string surface , which is softer than steel and can easily damaged by sharp edges & corners . When fully stretched and played-in , these strings present a uniquely warm sound combined with a softer & more flexible feel than steel strings , providing a truly heritage tone for period and early music specialists , authentic pizzicato for jazz players , and the perfect slap for our rockabilly friends . With natural gut strings , the music is always good .