This rotor valve string is engineered and designed specifically for brass instruments using rotor valves -it is not just re-purposed fishing line.  This string is strong, flexible, abrasion resistant, and will not stretch.The packaging also includes easy-to-follow instructions for stringing your instrument so even a novice can keep this small package in their instrument case and ready for an emergency. This needs to be a standard addition to every case’s storage pocket.This is a 2 meter package (6-1/2 feet).  Other sellers’ packages contain only 3 feet or even only 2 feet, but this will be plenty of string to last you for years without having to worry about wasting a little here and there or sharing with your friends.  Even though this is the finest string on the market, it is also being sold at the cheapest per-foot cost.This item has a 14-day return policy, so relax. Refunds will be given as money back, less shipping and handling fees.