With the General Tools 820 Metal Marking Gage, Single Bar you can easily trace the edge of a flat surface for ripping and cutting. The steel bar features an engraved, graduated ruler for making accurate measurements. The needle point scriber easily marks wood, plastic, hardboard and other materials. General Tools is a recognized leader in designing and developing specialized precision tools dedicated to delivering exceptional customer service. We encourage artisans and DIYers to work smarter, measure better, and repair more productively.