Oregon® Pro-Am Micro-Lite™ Guide Bars 20” are bars for the semi-pro and occasional woodcutters using small to mid-size saws with .325” or 3/8” chains. These 20” in length, Pro-Am bars have a narrow-kerf sprocket-nose and slim-symmetrical contour that is light in weight, maneuverable, and reversible for long life. Available in a variety of lengths, gauges, bar mounts and more. Recommended saw sizes: Up to 3.5 cu in (57). Pro-Am bars feature Micro-Lite™ – narrow-kerf cutting systems that increase cutting efficiency and require less power from the saw than standard cutting systems. To obtain all the advantages of narrow-kerf cutting, use with narrow-kerf .043” 90 series chain.