The Series 604D Minihelic® differential pressure Indicating Transmitter combines visual monitoring with electronic control of low differential air or compatible gas pressures. This versatile device is ideal for building HVAC systems where local indication is needed during maintenance checks or when troubleshooting the system. The transmitter design employs the latest strain gage technology and operates in 2-wire control loop circuits. Separate Zero and Span controls plus a 4-screw terminal strip are protected in a gasketed side enclosure. Cable gland fits .10-.25" round cable. A 10-35 VDC power supply is required.