Catgut suture treatment produces roughly twice the stitch-holding time of plain catgut, but greater tissue inflammation occurs. Full tensile strength is extended to 18–21 days. It is brown rather than straw-colored, and has improved smoothness due to the dry presentation of the thread (plain catgut is wet). It is otherwise similar to plain catgut. Fast catgut suture is heat-treated to give even more rapid absorption in the body. The first known absorbable sutures were made of the intestines of sheep. The manufacturing process was similar to that of natural musical strings for violins and guitar, and also of natural strings for tennis
Guqin strings silk and also they were louder and more stable. A set could last many years and not break. The only drawback for traditionalists was that the strings had a harsh metallic sound which was considered inelegant. Another factor was that the strings could eventually wear the lacquer out requiring the qin surface to be repaired more often. Around 2007, a new set of strings were produced made of mostly a nylon core coiled with nylon like the metal-nylon strings, possibly in imitation of Western catgut strings. The sound is similar to the metal-nylon strings but without the metallic tone to