dampers, a frames to specification, ducting tapes, ceiling air diffusers, ventilation or air bricks, spring assisted ceiling access doors, concrete curbs, threaded 90 degree bronze elbows, ceiling fans, louvers, roofing caps, smoke dampers, time delay switches, hand tools, snips available from waldron of maryland, inc. based in baltimore, md. click the links below to visit our website or contact us via our profile page.