The Model 407 Bladder Pump creates consistent, high quality samples in all types of applications. It ensures there is no air/water contact during sampling. It meets the most rigorous US EPA standards for VOC groundwater monitoring. The bladder ensures that drive air or gas does not contact the sample, thus avoiding degassing or contamination of the sample. Bladders and intake filters are easily replaced in the field in just a few minutes – no special tools required. Excellent for either regular flow or low flow sampling, the stainless steel pumps can lift from depths up to 500 ft (150 m) below grade.