Strings (tennis) be more durable than many other types of strings due to its outstanding tension retention. This may help to offset the high initial cost. The use of a dense string pattern also generally improves the longevity of natural gut. Natural gut is produced by drying fibers extracted from a part of the cow intestine called the serous membrane, or serosa, which contains collagen designed to withstand the stretching and contraction of the intestine. It is this elasticity that makes the fibers useful for tennis string. Sheep intestines have also been used for racquet strings in the past. The first natural
Rubab (instrument) a membrane, covering the hollow bowl of the sound-chamber, upon which the bridge is positioned. It has three melody strings tuned in fourths, two or three drone strings and up to 15 sympathetic strings. The instrument is made from the trunk of a mulberry tree, the head from an animal skin such as goat, and the strings either gut (from the intestines of young goats, brought to the size of thread) or nylon. The "rubab" is known as "the lion of instruments" and is one of the two national instruments of Afghanistan (with the zerbaghali). Classical Afghan music often features