It seems to work effectively for the first X times ...
It seems to work effectively for the first X times (have not had a chance to calcualte the exact number) over about a month period.  I am sure it depends on how much you smoke - and, I forgot to reattach the cover a few times) but it seems to work as advertised.  Next time, I will count the nimber of puffs I blow through it and I will ensure covering it each and every night and update hte review
Rating: 4 stars