Drain Cleaning Attachment Head Type Chain Knocker Compatible Cleaner Series Ridgid K9-204 Connection Size 5/16 in Maximum Drain Line Inside Diameter 4 in Minimum Drain Line Inside Diameter 4 in Product Type Knocker Compatible Cleaner Manufacturer Part Number 64273 Application Pipe Wall Cleaning Cutter Length 4 in Cutter Type Chain Knocker Features For Hard-Walled Pipes For Wipes Scale Roots and Soft Blockages Fits Brand FlexShaft For Use With K9-204 FlexShaft(R) Machine