Bag design: each filter bag with a zipper, the zipper is plastic, so it 't rust and harm fish health, it is very ventilate for fish to stay inside for mesh grids, convenient for you to fill and empty bags, not easy for fish to escape Wide range of usage: it is suitable for filtering fine, charcoal media and smaller particle media, it is available for aquarium, swimming pool, pond and any other occasions material: The media filter bag is made of corrosion-resistant Polyester material, breathable and not easy to break, you for a long time usage; the mesh will not be blocked bubbles, improving the water and filter media usage time and efficiency. Place the mesh bag containing the filter media in the aquarium to keep the aquarium clean and clean. Suitable canister , power , wet/ dry , swimming pool and pond. Number of : the include 20 pieces white filter bags, 20 pieces black filter bags, 40 pieces aquarium filter bags in , enough for your usage in Color: Material: Polyester Size: . 15 x 20 cm/ 6 x 7.9 inches Mesh hole size: . 2 mm/ 0.08 inch Contents: 40 x Filter Bags Only the above content, other are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.