N° 961X Graduated Beam Compass Includes two 13" graduated beam bars and one coupling to accommodate circles up to 48" in diameter. Inch and metric graduations. Spring -loaded thumbwheel on the top of each slide assembly allows for smooth and precise adjustments. Comes complete with interchangeable ruling pen, pencil, and divider legs. Includes spare leads and needlepoint. Packaged in a protective case. N° 961B Beam Compass Includes two 13" ungraduated beam bars and one coupling to accommodate circles up to 48" in diameter. Spring-loaded thumb wheel on the top of each slide assembly allows for smooth and precise adjustments. Comes complete with interchangeable ruling pen, pencil, and divider legs. Includes spare leads and needlepoint. Packaged in a protective case.