Durable, easy-to-use Nalgene™ pumps are made of polyvinyl chloride and quickly attain and hold vacuum of 25" (635mm) Hg. The vacuum trigger release requires only one hand to operate and releases vacuum with the touch of an index finger. Adjustable vacuum release rate is also controlled by trigger on pump. The smaller size has a pumping rate of 15 cc/stroke and 3 psig (0.21 bar) positive pressure at the exhaust port. Larger size has rate of 36 cc/stroke and 7 psig (0.48 bar) positive pressure at the exhaust port. Full blank port pressure is obtained with only two strokes. Pumps feature a removable cover on exhaust port and trigger to release vacuum without disconnecting from the line. Without vacuum gauge. This economy version is ideal for field or lab use. Nozzle fits standard 1/4" I.D. tubing. Supplied with two ft. length of Nalgene™ 180 Clear Plastic Tubing.