The Gilian 5000 provides automatic constant flow from 800 cc/min to 5000 cc/min. When used with a low flow module, they also handle low flows from 20 to 800 cc/min under constant pressure control, such as required for multi-flow sorbent sampling. These pumps offer significantly higher back-pressure capabilities than competitive pumps thanks to a more advanced pneumatic design and a more powerful power source. As a result, dense particulate buildup on the filter, such as with dusty environments is far less likely to trigger premature pump shutdown and an incomplete sample. See the chart on the following page for back-pressure information.