The DryerJack is the first dryer roof vent termination designed to virtually eliminate the back pressure. Many common roof terminations used in our area have an airflow reduction of 0.35 to 0.45. By comparison the DryerJack has less than 0.00 airflow reduction!
This cutaway view shows why the new low profile DryerJack 466 is so efficient. In fact studies show that this vent termination affects airflow by less than .01 water column inches of pressure. When the dryer is on, the internal flap opens fully, reducing the loss of air velocity. When the dryer is off, the flap closes to prevent rain, birds, squirrels, etc. from entering your dryer vent and ducting.