JBL Uni Bloc i-Serie consists of 100% neutral synthetic material that realeases no pollutants in to your water. The pore density measures 20 ppi. Round cross section with T-Profile for JBL Cristal Profi i 40 Triangular profile for Cristal Profi i 60 bis i 200 Order other filter sizes with the following links JBL Micro Mec fuer Cristal Profi i 60 bis i 200 JBL Clear Mec fuer Cristal Profi i 60 bis i 200