The black plastic material in your Jet system is the BAT® media pack. Jet BAT® media is essential to the treatment capabilities of your system. Special precautions should be taken when servicing and pumping your Jet system to avoid damaging this media and the performance of your system. Do not attempt to clean or remove the media packs, damaged packs are expensive to repair or replace. Contact your local Jet distributor if you have any questions or feel that your system is in need of service.