Designed for the PSM-500 Tube Cleaning Drill, the hollow shafts are available in many lengths and connect to brushes, buffing tools, hollow carbide drills and twist drills to clean straight heat exchanger tubes. Drill cleans tubes 5/16"-1" (7.9-25.4mm) I.D. Hollow Shaft 3' (0.9m) long with coupling (C-1P) to adapt 5/16" (7.9mm) brushes, coupling (C-2P) to adapt 3/8" (9.5mm) brushes and coupling (14-28) to adapt 7/16"-1" (11.1-25.4mm) brushes and all buffing tools to PSM-500.