1950-20-2F is a series 1950 compact, low cost explosion-proof differential pressure switch combines the best features of the popular Dwyer® Series 1900 pressure switch with an integral explosionproof and weatherproof housing, making it an exceptional value for either application. It is CE, UL and CSA listed, FM approved for use in Class I, Div 1, Groups C and D, Class II Groups E, F, and G and Class III hazardous atmospheres NEMA 7 and 9. Rain tight NEMA 3 (IP54), weatherproof features include a drain plug and O-ring seal in cover. Electrical connections are easily made by removing front cover. For convenience the set point adjustment screw is located on the outside of the housing. Typical applications include HVAC applications, process applications and all-weather applications.