Most popular series combines advanced design and precision construction to make these switches able to perform many of the tasks of larger, costlier units. Designed for air conditioning service, they also serve many fluid, refrigeration, oven and dryer applications. For air and non combustible compatible gases, Series 1900 switches have setpoints from 0.07 to 20½(1.8 to 508 mm) w.c. Set point adjustment is easy with range screw located inside conduit enclosure. Internal location helps prevent tampering. UL, CE, CSA listed, and FM approved.