Validyne Engineering, Northridge, CA, offers the Model DR800 fast-response draft range transmitter that senses low pressures for process heater flame instability detection in low-emission burner retrofits. The transmitter can measure pressures down to ±0.25 in.H2O varying at up to 10 Hz with no loss of sensitivity due to electronic damping or internal mechanical filtering. Output is a 4–20 mA signal. The variable reluctance sensing element has a single moving part allowing the device to detect high frequencies at very low pressures. The device has a NEMA 4 rated housing and is FM approved for Class 1, Div. 2, Groups B, C, and D.