Sink-Fast (TM) fly line cleaner is designed specifically for sinking lines and saltwater lines. Sink Fast is a non-toxic water based silicone product that cleans, lubricates and protects fly lines from UV damage. Unlike other cleaners, Sink-Fast is not hydrophobic and will actually improve sinking line performance. Simply spray onto a clean cloth and wipe the line down. No buffing or time is required to set and the product can be used directly on the water.