Bass Guitar Gut Strings

 
 Bass guitar gut strings will give you the best rich tone, using the traditional catgut, rather than nylon or metal, like most modern strings. Bass guitar gut strings are usually made from sheep intestines. Bass guitar gut strings come in two varieties: plain gut, and gut wound with metal. For a bass guitar, the gut strings would most likely be wound in metal.
 

See below for the more common bass guitar strings: