Rivers FLYDRY™ is a premium dry fly floatant with a twist. Use the brush to work it into an emerger and it will produce an air bubble around the fly that trout find irresistable! FLYDRY™ works as good as the Brand F stuff at a fraction of the price and will actually improve the floatability of cdc flies. Hogwash you say? It's true, as excellent as cdc is as a dry fly material, it can be hard to keep dry on damp or cold days like when the BWOs are hatching but not with FLYDRY™.