We understand your concerns about plastics and that is why we use so little in our products. We originally tried to make our products entirely plastic free but it has proven very difficult to achieve when dealing with a device that requires water tight to perform well.
Still, we are very proud to say that we use very little plastic and that none of the plastic parts are single use parts. In fact all the parts of our filter cartridge are used over and over for several years. And when it comes to that all the parts are also recyclable.
To answer your question, the aquacristal cartridge only has a few PP made dividers to prevent the layers from blending together. We chose PP because it's one of the most stable and neutral plastic out there. Also the products have been designed so that the water is very little in contact with plastic parts during and after the filtration process. The cartridge and tap seals are made of premium food grade EPA silicone.
We're not perfect, but we strive to be the best we can be, and our efforts have resulted in a truly eco-friendly alternative to residential water filtration.