Series 677B Differential Pressure Transmitters are designed to measure pressures as low as 0.1 in w.c. with ±0.4% accuracy. Use Series 677B for building energy management systems, environmental pollution control, oven pressurization, lab and fume hood control, HVAC and VAV applications. The transmitter features 15 psid overpressure, reverse polarity protection and EMIRFI protection. Internal regulation permits use with unregulated DC power supplies. The NEMA 4 housing allows for versatile mounting locations and integral mounting tabs simplify installation.