The MAMAC Systems A-520/523 Series duct and room static pressure sensors for pressure transmitters and pressure switches are used in dirty filter, duct static and room pressurization applications. The A-520 is designed to pick up static pressure in a duct, plenum, air handler or other HVAC equipment. Use the A-523 to sense pressure in rooms, laboratories, hospital operating theaters, clean rooms or any other application in which the area is under positive or negative pressure. The A-523 is designed to interface with the MAMAC PR-274/275 low pressure sensors to provide a low cost labor saving alternative to expensive field derived solutions.