The French SKN is a tapered leader designed for nymph fishing. Its length and profile are chosen together to maintain contact with the nymphs at the desired fishing distance.
The tapered profile transmits the casting motion from the butt to the tip. Transparent versions come in two different tip diameters; therefore, color and length alone are not enough to identify the model. Compare the profile specified for each version before preparing your tip. The leader can be cut to size, but shortening either the heel or the tapered tip affects the balance of the rig differently.