powerful fan controller that ensures a constant negative pressure in your grow room maintains correct temperature and is a must for a good result our controllers have a 1.8m sensor so your controller can be placed outside your grow room/room. it is important to choose a controller with higher amps than the one your suction boxes use at startup. please contact us if you need help with the correct climate controller for your ventilation. SMSCOM SPC is a powerful dual fan controller that automatically adjusts the speed of both an inlet and outlet fan to maintain a correct temperature and optimum air pressure inside the room. Automatically calculates the exact running speed of your fans to maintain the temperature you have set. The highest and lowest speeds that the fans can operate between. Extremely accurate temperature controlVery smooth operation of the fan speedOptimizes the air pressure automaticallyNo need to adjust the fan speeds yourself, SPC does it all for youMin / Max fan speed can be set as requiredThe unit can be calibrated to run with your chosen set of extraction machines. This keeps humming and buzzing to a minimum on all fan types.Make your ventilation system run quietly and efficiently1.8m probePlug and play – no wiring required5 year warranty