The size/density separator employs vibratory screening to remove undersize particles, and airflow to simultaneously remove low bulk density materials. According to the manufacturer, it efficiently separates fines and chaff from grain products; fines, angel hair, strands and film scrap from plastic pellets/regrind; fibers, saw dust and wood flour from wood chips/shavings; and other undersize and low bulk density matter from on-size products. Material is fed through a port on the unit''s hood over a series of strategically placed internal trays, and onto a vibrating, fine mesh screen that moves on-size material in controlled flow patterns toward and through a discharge port at the screen''s periphery. Heavier fines and a portion of the lighter fines pass through the screen onto a chute leading to a lower discharge spout. Simultaneously, air drawn into the base of the air-tight chamber flows upward, drawing the balance of low density fines into an air stream that increases in velocity before venting to a cyclone and/or dust collector. The separator is available in 24- to 100-inch diameters, in carbon steel or stainless steel, and is offered as a stand-alone unit or a complete system integrated with a dust collection system, exhaust fan and electrical controls on a mobile frame, ready to plug in and run.