Ideal for those pursuing finicky trout, the Rio Mainstream Sink Tip Fly Line helps optimize rod performance with its slightly heavier, shorter head length. Rio’s 12′ weighted tip is precisely tuned to sink at a rate of 3 per second. With a supple, memory-free core with slick coating this fly line excels in coldwater. Slightly heavier than standard fly lines “loads easily Weighted tip tuned to sink at a rate of 3 per second Supple, memory-free core with slick coating excels in coldwater.