A hand labeller having a plurality of rotatable print wheels with selectable print types disposed on the periphery of each print wheel and a selector spindle for positioning selected print types at a printing zone of the print wheels. The selector spindle includes a reduced diameter portion which engages and slides in an arcuate slot in the labeller housing if (a) the spindle is fully pushed into the print wheels and (b) the labeller is operated to rotate the print zone of the print wheels to a label printing position. If the spindle is not fully pushed in, a large diameter portion of the spindle will engage the arcuate slot, the latter portion being too large to enter the slot whereby the print zone of the print wheels is inhibited from rotation to the label printing position.