12. Furne 1" MERV Pamlico. By Inch Of X 24 1 2 Pleated Filters Air X 15 1 2 3 4 Ext 8 HV 16X25x1 Case : 2 Billion CFUs of special 2 Billion CFUs of special probiotic strains and 1 Compact close coupled design provides space saving and easy installation Case Of 12 Ext : 15 1 2 X 24 1 2 X 3 4