Hach 3400 Digital Contacting Conductivity Sensors. These enhanced performance sensors are manufactured to exacting tolerances using high quality, rugged materials for demanding applications including ultra-pure water, clean-in-place (CIP), and boiler/condensate monitoring. Each sensor is tested to determine its unique, absolute four-digit cell constant. Also, each sensor has a Pt 1000 RTD temperature element built into its tip for exceptionally fast response to changes in temperature with ±0.1ºC accuracy. The sensors measure from theoretically pure water (0.057 µS/cm or 18.2 MΩ) up to 200,000 µS/cm. Hach’s sc Digital Controllers accept multiple digital sensor inputs, and can be user-set to measure conductivity, resistivity,TDS, salinity, or one of six calculated measurements. Compression fitting sensors feature titanium electrodes and a compression fitting for universal installation with up to 4 inches (102 mm) insertion depth. The 1/2-inch or 3/4-inch male NPT compression fittings are offered in Kynar® (PVDF) or 316 stainless steel. A longer version of this sensor is available for use with a 316 stainless steel ball valve hardware assembly to insert/retract the sensor from the process without stopping the flow. The longer version can also be used for insertion through a compression fitting. Maximum insertion depth is 7 inches (178 mm).