Orvis Mirage LeaderThis fly fishing leader is preferred in spring creeks, stillwater fly fishing situations, for use with large streamer fly patterns, or when fly fishing with nymphs or dry flies in clear water where trout are fished over heavily.This knotless fly leader is more invisible to fish than nylon fly fishing leaders. Refractory index only .09 different than water compared to 1.53 for Super Strong nylon.Incredible abrasion resistance fly fishing leader material.Mirage fly fishing leader absorbs no water. In comparison, breakage and knot strength decrease 30% in nylon materials with water absorption.New fly fishing leader tapers have resulted in a 20% average increase in butt diameters in all Mirage leaders for more efficient transfer of flyline energy to leader.