420 Purifier is made of quality materials. The casing is made of robust wood panels manually assembled and glued into a massive structure. There are two aluminium sheet metal plates inserted between the panels which serve as a chamber containing activated carbon. Air circulation is provided by a centrifugal fan with airflow of 270 m3/h. Because the lifetime of this type of fan exceeds 50,000 hours, and because each 420 Purifier is manually assembled, checked and tested, this device will still be working many years after its purchase.