This lightweight polypropylene pump provides a constant vacuum when hooked to a standard faucet; it operates efficiently with water pressures as low as 7.5 psi for minimum water consumption. It has a maximum free-air pumping capacity of 11.5 liters per minute at a water-flow rate of 6.5 liters per minute. Ultimate vacuum: 28.5" Hg. Supplied with integral check valve, 3/8" NPT connecting thread, and 4 3/4" length of tubing for insertion in discharge end.