RIDGID offers a wide variety of Flex Shaft accessories in different sizes for the most cleaning efficiency on the jobsite. Depending on pipe size, pipe material and blockage, there are different chain Knockers and Brushes for every job. Knowing when to choose Brushes or standard, carbide tipped or penetrating head chain Knockers can help you get the best performance out of your machine. This bundle includes a carbide tipped, triple-chain knocker (catalog number 66588), double chain knocker (catalog number 71848), and Penetrating Ball Head (catalog number 71848) for use with the RIDGID Flex Shaft K9-12, K9-102+ and K9-204+ drain cleaning machine and attaches to the end of the 5/16 in. cable (not included). This style knocker + head is designed to clear grease, scale, light roots, wipes and other soft blockages found in 4 in. pipes.