"HYDRAULIC CLAMPING SYSTEM; PISTON CLAMPING SCREW EXERTS FORCE ON THE PRESSURE PISTON THAT PRESSURIZES THE HYDRUALIC FLUID, HYDRAULIC FLUID EXERTS HIGH PRESSURE ON THE EXPANSION SLEEVE TO COMPRESS TOOL SHANK; TOOLHOLDER SIZE IS 0.250 IN. DIA., 3.250 IN. LG. TOOL; 2.480 IN. DIA. SHANK FLANGE; CHUCK LARGEST OUTSIDE DIA. 1.970 IN."