The Cobra 4-Piece Plumbers Cutter Set offers an assortment of cutter tips designed to explore and break up stoppages in your drain. For use with Cobra 5/16 in. x 50 ft. Cable Drum Machine (Model # BC260C). Attach to slotted end cables to clear a variety of tough clogs. These cutters are made of heavy-gauge, tempered steel. The set includes: straight boring head, spear-head blade, side cutter and grease cutter. To use the set, select the tool that is needed. Place the tool in the middle of the slot on the cable in the drum machine. Using the screw in the package, screw it into the center hole of the side of the cable. Tighten with a screwdriver. Confirm the tool is securely attached to the cable before entering the cable into the drain. Remove clog. Once complete, remove the tool from the cable, reattach to key ring, and save the screw for later.