The best all-around of Wein's Air Supply products
First, if you suffer from airborne allergies, the Wein Air Supply product should greatly help you.
I am very sensitive to formaldehyde which is just in some many things, and the Air Supply has helped me enormously with this problem.
Frankly over the years I've tried the 1500, the 500B (This one amazon is identifying as 500), and the 150MM.
Less than 80 ft/min airflow as in the 1500B seemed helpful but not as usefull as the 80 from this model.
The 120 ft/min from the 150MM model is more powerful but can be annoying as well. I like to use that model only when I'm in extremely smoggy conditions, like the train depot. I call it "the screamer" because it's so noisy.
So, from the selection that Wein offers, I believe the 500 (or AS 500B) at 80 ft/min airflow and only mildly noisy is the best of them all. I wear mine all the time (except home).
Basically I recommend Wein Air Supplies as well as this particular model....more info