Dwyer Instruments’ Series 646B Differential-Pressure Transmitter is designed to be used with clean, dry air, and other non-corrosive gases. Each unit features a flame-retardant enclosure and is designed for circuit-board mounting. The transmitter measures differential pressure at an accuracy of +/-2.0 percent full scale down to 0.5 in water column. The transmitter contains a stainless steel sensor that provides resistance against corrosion. The transmitter offers stability, low hysteresis, accurate operation over a broad temperature range, and insensitivity to vibration. The transmitter is a good fit for VAV systems, filter monitoring, HVAC fan control, building pressurization, and leak-detection systems.