The whip brush and first rod are combined in the TPowr system. This item comes with 12" and 24" strands so you can cover all flue sizes from 5" to 16"x16". Easy to change strands, the ToolLess design is shown in the video. In round flues rotate in either direction. In sure and rectangular flues, the whip will tend to walk in the direction of rotation. Simply reverse the drill rotation once you reach the top of the stack and come back down in the opposite rotation which will get all four corners swept!