The optimised drive unit for driven tools is equipped with an improved VDI40 interface. For maximum repeatability, the straight shank and the face contact are manufactured much more precisely than standard tool holders with a different geometry. A particular advantage is the internal coolant supply (IKZ) through the spindle. Variants for radial and axial tools are available. They accept tools with either ER16 or ER20 collets. In the version for radial tools, direct hydraulic clamping in the milling spindle is available as an option. This additionally increases the damping and concentricity of the clamped tools.