The collection is made up from the following:
CDC Black Gnat Parachute
CDC Shuttlecock Black
CDC Shuttlecock Red
CDC Shuttlecock Olive
CDC Shuttlecock Yellow
CDC Standard Yellow
CDC Standard Black
CDC Standard Claret
CDC Standard Blue Winged Olive
CDC Parachute Olive
CDC Black Parachute
First of all CDC is an acronym for cul de canard. This is a type of feather, used for fly tying, which is located near the preen gland on most birds such as ducks and geese.
The structure of the feather gives it buoyancy, thousands of little barbules that extend from the numerous shafts within the feather act like a raft trapping air bubbles. Its these bubbles that keep bringing the feather back up to the surface. Because of this, it is a waste of time adding floatant to CDC flies, as this will tend to cause the fly to sink because the floatant will block the barbules and prevent them from trapping air.