Bag design: Each filter bag features a plastic zipper that does not rust and is safe for fish health. 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 media. Suitable for use in aquariums, swimming pools, ponds, and other similar applications. Quality material: Made from corrosion-resistant polyester, these filter bags are durable, breathable, and resistant to tearing for long-term use. 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 or 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, providing ample supply 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: Light reflection and differences in display screens may cause slight variations in color between the image and the actual item. Measurement allows an error of +/- 1-3 cm.