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
Ukulele of an old wooden cigar box. These instruments usually have four strings; some strings may be paired in courses, giving the instrument a total of six or eight strings (primarily for greater strumming volume.) The strings themselves were originally made of catgut. Modern ukuleles use nylon polymer strings, with many variations in the material, such as fluorocarbon, aluminium (as winding on lower pitched strings), and Nylgut. Instruments with 6 or 8 strings in four courses are often called taropatches, or taropatch ukuleles. They were once common in a concert size, but now the tenor size is more common for six-string