The Seachem Polishing Pad for the Tidal hang-on filter is a top of the line mechanical filtration media designed to quickly and efficiently remove fine particles and debris as well as polishing water for unmatched clarity. The pads are reusable, but need to be regularly cleaned by thoroughly rinsing the pad under clean water. The pad must be replaced if during rinsing it does not get clean, or if it has noticeable signs of wear and tear. Comes in a pack of two.