Anyone who has waded rivers for steelhead, especially winter steelhead, knows that often water conditions can change drastically in a matter of hours. Tube flies allow steelhead fishermen conditions. By changing the type of tube they use (Plastic, Metal, Bottle, Shumakov, etc.), allows more control over the depth and action of the fly. Of course tube flies also have the advantage of having a larger fly with a smaller hook, exactly what is called for to drag out large steelhead.