SMC's ALTS flow switch represents the state-of-the-art in gas and liquid flow switching and liquid level control. This device continues the SMC tradition of providing the highest quality flow instrumentation. Flow & level detection is accomplished by using a high-resolution thermal differential technique. The sensor consists of a pair of matched Resistance Temperature Detectors (RTD’s). One RTD uses a self-heated constant DC current while the other RTD is unheated and provides an accurate process temperature reference. The temperature differential created between the reference and the heated RTD pair is a function of the density and/or velocity of the media in which the sensor is in contact. The sensor and wetted parts are comprised of durable 316L stainless steel, all welded construction with no moving parts. The switch is easy to install and adjust; providing reliable, low maintenance performance in the most demanding applications.