The PRU is a self-contained Sample Draw Pump Unit that can be utilized with most gas detectors. It contains a pump that is designed to draw samples of air from hard to access locations such as shafts, tall ceilings, wells, pits, small rooms and other locations where it is difficult to install gas detectors. The sample draw pump pulls air from the sampling area through tubing connected to the inlet port, over the sensor and exhausts it from the outlet port. If the gas readings are higher than a specified set point, the gas detector will go into alarm. The unit can be purchased with 24 VDC or 24 VAC operating power and includes a sample pump, adjustable flow meter, in-line particulate filter with a water tight, polycarbonate enclosure. The tubing and flow adapter that fits CETCI gas detectors are sold separately. The Sample Draw Pump Unit is not rated for use in hazardous areas because the pump is not intrinsically safe.