Bag design: Each filter bag features a plastic zipper that resists rust and is safe for fish. The mesh grid construction ensures good ventilation, making it suitable for holding fish temporarily. Easy to fill and empty, with a secure closure to help prevent fish from escaping. Wide range of usage: Ideal for filtering fine media, activated charcoal, and small particle filter materials. Suitable for use in aquariums, swimming pools, ponds, and other filtration applications. Quality material: Made from durable, corrosion-resistant polyester fabric that is breathable and resistant to tearing. The mesh resists clogging, helping to improve water quality and extend the life and efficiency of filter media. Usage: Place the mesh bag filled with filter media into your aquarium filtration system to help maintain clean water. Compatible with canister filters, power filters, wet/dry filters, swimming pools, and ponds. Package includes: 20 white filter bags and 20 black filter bags, totaling 40 filter bags. Sufficient quantity for regular use. Color: Black and white Material: Polyester Size: 15 x 20 cm / 6 x 7.9 inches Mesh hole size: 2 mm / 0.08 inch Package contents: 40 x Filter Bags Note: The package includes only the items listed above. Other products are not included. Lighting and display differences may cause slight variations in color between the image and the actual item. Measurement may vary by +/- 1-3 cm.