An automatic water sampler is essentially an intelligent pump that takes water from a source and places it in one or more bottles. Samplers can do this based on time, flow rate, or some other externally measured parameter, such as rainfall or water quality. An autosampler typically uses one of two technologies for sampling: a peristaltic pump or a vacuum pump. A peristaltic pump consists of two or more rollers that rotate at high speed and compress the pump tube, creating pressure or vacuum, depending on the direction of rotation, air is forced out in the tube and replaced by water. Hach Lange AS950 autosamplers take and store water samples for further laboratory analysis. The AS950 samplers are available in three versions: portable, refrigerated for indoor use, and all-weather. HACH automatic water samplers are compatible with a variety of bottle sizes, quantities and materials. The AS950 is configurable to meet all sampling requirements by combining a controller, base, bottle set, accessories, and sampling program features. Each AS950 features a peristaltic pump with spring loaded rollers for long tubing life and a liquid detection sensor for best-in-class volumetric accuracy. The Hach AS950 is easy to program for a wide range of applications including industrial pre-treatment, storm water, process control and waste water sampling.