Strings are one of the important elements of structuring sounds. It is difficult to find satisfying strings and features adapted to each instrument. Some strings have power(volume) but not a good balance. Others have good balance but low tension. It does not exist a product giving total satisfaction. Though buying and trying strings many times, they were always inadequate! (many customers may have felt the same way). Finally,"WORTH STRINGS" decided to produce and sell these excellent Fluoro-carbon strings. Fluoro-carbon is used for fishing lines. They are flexible. Sturdy against haul. Unchangeable in any type of environment.