Bag features a large-diameter, vertical drip chamber with a Mono-Flo™ anti-reflux valve that automatically closes when the bag is tilted, lifted or laid on its side. The 2000mL, oval-shaped bag allows even filling and complete drainage, eliminating dead space. A closed-system aspirating port on the tubing permits repeated fresh urine sampling. Tubing is 11/32" in dia. for better urine flow.