reduce minerals in the water Box contains 1 Filter Item # HS-1932 UPC854689001205 Easy to Use : Step One - Before the low use, s0ao the filter for 30 minutes Step Two - Place the presoaked filter into the humidifier tank Why Use A Demineralization Filter ? . A demineralization filter minerals released into the air caused by al dente water. For best results the filter after every 30 - 40 fillings under natural use or when the humidifier has not been operated for an rolled out period of time. : To determine if this filter is matched with your humidifier, please zoom in on product image that shows models .