Screw guides are used when a positioning precision of less than 0,1 mm (worm drive screw) is required, when using very low speeds, and when the unit has to be of compact size. In the screw guides the fitting of the motor directly coupled to the screw facilitates the use of very low torque motors. Screw guides are supplied with both spherical worm screws and with trapezoidal screws, depending on needs.