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
Experimental musical instrument of the usual two (counting the nut as a bridge). By adding a third bridge, one can create a number of unusual sounds reminiscent of chimes, bells or harps A 'third bridge instrument' can be a "prepared guitar" modified with an object – for instance, a screwdriver – placed under the strings to act as a makeshift bridge, or it can be a custom made instrument. One of the first guitarists who began building instruments with an extra bridge was Fred Frith. Guitarist and composer Glenn Branca has created similar instruments which he calls harmonic guitars or mallet guitars. Since