The Model 425 Discrete Interval Sampler is a stainless steel groundwater sampler, with LDPE tubing mounted on a convenient reel. Discrete interval sampling is ideal for obtaining truly representative groundwater samples from below floating product layers, or for obtaining samples of the product itself. The Discrete Interval Sampler can also be used to profile open bodies of water, boreholes, and to collect samples from distinct levels or points of inflow. The Discrete Interval Sampler is a passive sampler that is pressurized when lowered and upon retrieval, to prevent water mixing at different levels. Designed to give zero purge samples.