These rods are used for general purpose domestic drain and chimney cleaning. This 12pce set includes 10 rods with two attachments, 100mm Rubber Plunger & 50mm Double Worm Screw. Made with universal joints they simply screw together & should only be rotated in a clockwise direction. The Double Worm Screw end is used to retrieve an obstruction. The Rubber Plunger is used to create a build up of pressure which in turn forces the obstruction to clear. Rods are both crimped & pinned for added security.