64 x Filter Bags: 40 x a + 24 x b 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 its mesh grids, convenient to fill and empty bags, not easy for fish to escape Quality material: The media filter bag is made of - Polyester material, breathable and not easy to break, you for a long time usage; the mesh not be blocked , improving the water quality 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 filters, power filters, wet/ dry filters, swimming pool and pond. ,breathable and ,great for use in canister filter system. zipper:unlike the Metal zipper,our filter bag zipper is plastic,not contain metal which may easily get rust and pollute your water,and convenient to fill and empty bags. Wide usage:this mesh filter bag fit for most kinds of filter media, like Pelletized Carbon, Bio Balls, Ceramic Rings, Ammonia Remover,suitable for aquarium, swimming pool, pond and any other occasions.(Please note, it for finer particles) you for a long time usage. Color: black and white Material: Polyester/nylon Size: . 15 x 20 cm/ 6 x 7.9 inches Mesh hole size: . 2 mm/ 0.08 inch Package Contents: 64 x Filter Bags Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.