Product review (1 stars): no longer good quality
Do not be fulled by high reviews.  Their quality has plummeted.  I have a collection of fine acoustic guitars and buy  several of these at the beginning of each season.  Over the past 3 years these have gotten steadily worse and worse.  I just changed my filters 5 minutes ago.  The paper is not fully perforated so the segments cannot even be separated.  This is a manufacturing defect from a worn out cutting machine.  They are cheap-ing out and not making good parts.  And because I buy mine at the beginning of the season I am stuck and can't even return them.

Pick a different brand