In a toothed piece for a geared motor, series of geared motors and connection, the toothed piece, for a connection with a motor shaft of the electric motor, having at least a first toothing in a first axial region, and having at least a second toothing in a second axial region, the second toothing meshing with a running toothing of a further toothed piece of the gear unit. The guide plate curves upward above the separating rod, having its front edge positioned higher than the separating rod to let labels move slantingly upward along the guide plate and stripped. In a first position of the unit, the actuating element is positioned such that the first sensor and the second sensor each output a first sensor signal. The rotor assembly comprises an inlet for receiving said mixture of substances, an outlet from which said substances are ejected from the rotor assembly during use, and a flow path for providing fluid communication between the inlet and outlet, wherein the outlet is positioned more radially outward from said axis than the inlet. A gate electrode is over the gate dielectric. Since the handle and the post are defined with a containing hole and a through hole respectively, when the user releases the pressing ring, the length of the working post with respect to the handle can be adjusted, and one end of the working post can be inserted into the containing hole and the through hole of the handle and the post.