DC tapered sinking fly Fly Lines are easier to cast than traditional level sinking Fly Lines. RIO?s manufacturing process enables smoother casting and consistent sink rates. With density compensation, the sink rate of the tip equals the sink rate of the midsection, allowing the tip to sink first and put the fly in the strike zone. The DC Type 3 and the DC Type 6 sinking Fly Lines together with the AquaLux« Fly Line are the mainstay for lake fly fishers. Type 6 sinking Fly Lines are made on a Powerflex core. Type 6 4WT and 5WT Fly Lines are made only by RIO.