Replace metal-type troughs with the lightweight, corrosion-proof and quiet Nalgene™ Polypropylene Pneumatic Trough. This trough features tapered sides for nesting and a built-in gas inlet. There are no sharp corners or separate parts to lose. The built-in platform accommodates four 250mL bottles. Gas tubing passes through a loop to prevent liquid from flowing into gas line. Liquid inlet and outlet connections accept 1/4" I.D. x 3/8" O.D. (6.4 x 9.5mm) tubing (tubing sold separately).