Buy 2 and rotate weekly to let filter dry whatever moisture has accrued
5 Stars on longevity if you insert into the mouth piece:<br />  1 layer of 5 cotton balls set side-by-side<br />  Top with 3 cotton balls insuring any open areas on the bottom layer are covered.<br />Change cotton any time.  Remove cotton when letting filter dry.<br />The cotton absorbs a lot of moisture from smoke exhalation, extending the longevity  greatly.<br />These are very inexpensive considering their overall worth aafter a few cheap tweaks.
Rating: 5 stars