Collar: Any length you want. Typically I use longer fibers of marabou, FoxxFurr, and a wide variety of long natural furs. I also add flash materials, rubber legs, etc., to the collar. Insert the materials in a spinning loop, twist it tight to make a "3-D" hackle, and wind it on. Apply the collar as lightly or as heavily as you want. The heavier the collar, the more water the fly will push.