Hi-Tech Braided Valve Cord (2 meters) This is best cord for rotary valves we've come across. We use it on all professional horns. The braided synthetic fiber is naturally lubricated so the string slides easily across itself and the valve components with almost no friction or wear. It is very strong, has virtually no stretch and virtually no "memory" so it does not retain curves. On a properly adjusted instrument it will produce a noticeable increase in valve speed. This 200lb test cord is about 2/3 the diameter of our 80lb dacron cord.