These strings are usually used on Baroque instruments by those musicians playing historical performance practice. Consequently, the gauges are set to the pitch of a=415. The tone is full and warm with a powerful fundamental and complex, pleasing upper partials.This viola beef serosa string set consists of a double-length (64", 160cm) a-1 plain gut medium gauge .76mm string; a single-length (32", 80cm) d-2 Pistoy gut medium gauge 1.04mm string; a single-length (25.5", 65cm) gut core silver-wound G-3 medium gauge .82mm string; and a single-length (25.5", 65cm) gut core silver-wound C-4 medium gauge 1.12mm string.All strings are made with beef serosa with a natural finish. The G-3 and C-4 strings come with a ball end, but the others have plain ends and can be knotted as necessary. Instructions on how to tie a string knot are on the back of each package.Beef serosa has a higher tensile strength than does sheep gut, so this string is useful for instruments that require extra durability. If your instrument has a longer string length which puts it beyond the comfortable range for sheep gut strings, the beef gut would be a good choice for string selection as it will stand the strain a little better. Treble gut is processed to be a little harder than other kinds of gut, and it also has a lower twist of about 15 degrees to increase the strength.#Hand-made in the USA by Gamut Music, Inc., a leader in the revival of early music strings and instruments. Gut strings are not intended to be used with fine tuners or string adjusters, and those devices should be removed before installing the gut string on the instrument.All Gamut Academie strings (pure gut and gut/metal-wound) are made with beef serosa unless they specifically say "Sheep Gut." All pure gut Tricolore violin and viola strings are made with sheep gut; gut/metal-wound Tricolore and all Red Diamond strings are made with beef serosa.Gamut gut string gauges are approximate (≈) diameter. Meaning, that while a ≈0.60mm string is polished in the workshop to a diameter of 0.60mm, changes in ambient humidity, temperature, shipping, and storage conditions can cause to string to expand or contract slightly.