Guardian Digital Airflow Monitor senses and alerts the operator to low airflow conditions. Each monitor includes a face plate with circuit board, electrical power pack, vinyl tubing, side wall flow tube adapter and wiring instructions. From the monitor's face plate, the user can easily select and calibrate a setpoint between 50 and 250 fpm using a velocity meter. An LCD displays actual face velocity. If the hood's face velocity falls below the programmable set point, an audible alarm sounds and the an alarm indicator glows red. The audible alarm can be muted with one touch.