SPECIALTY SINKING TIP FLY LINE SERIES, WITH ULTRA- SLICK PERFORMANCE.RIO's Avid 24ft Sink Tip series of fly lines is designed to get your flies down in the water column and is now developed with RIO's most advanced fly line coating technology at an approachable price. The lines have a 24ft long sink tip to present flies to deeper-lying fish while employing a taper design crafted for easy casting performance. Each line is built on a supple, memory-free core with our SlickCast coating technology, creating the slickest and most durably fly lines on the market.