8mm I.D. HSK-63C GUHRING Hydraulic Chuck w/Coolant & Increased Clamping Force, 60mm Gage Length HSK-C to ISO 12164-1 / DIN 69893-1 | balanced to G2.5 / 25,000 RPM | tremendous clamping force | maximum concentricity deviation 3 um | axial length adjustment | for tool shank tolerance h6 | includes adjustment screw, Series no. 4900 | includes hexagon chuck key, Series no. 4912 | order coolant supply set, Series No. 4949 separately. The use of reduction sleeves greatly improves the usefulness of a hydraulic chuck. Clamp directly on the cutting tool shank or use a reduction sleeve to hold a different diameter tool shank and increase transferable torque by approximately 25%. The reduction sleeve outside diameter must match your hydraulic chuck's nominal inside diameter. Reduction sleeves are available in 6 different O.D.s; 1/2\