This booklet contains information regarding the company's products, including catwalks and plenum curbs. Today's buildings, with their advanced air-handling system designs, feature small, space-saving, interior ductwork and a large (often 30-ft-high) plenum curb on the rooftop, according to the manufacturer, Conn-Fab Sales, Inc. (Uncasville, CT). Once the air handler is installed on that curb, maintenance access can be a problem. The company says its catwalks are cantilevered from the plenum curb itself, so no part of the catwalk or its suspended access ladders at either end contact the roof.