Filter bag size: 15 x 20 cm/ 6 x 7.9 inches; Mesh hole diameter: approx. 2mm, perfect for use with activated carbon, bio-ball, zeolite, pellets, gravel, ceramic rings, ammonia remover or any other aquarium filter media, not applicable for fine, granulated charcoal media and smaller particle media. Durable material: the media filter bag is made of corrosion-resistant polyester material, the mesh will not be blocked by air bubbles, improving the water quality and filter media usage time and efficiency. Thoughtful design: our plastic zipper is more safety for media filter, reusable and great for long time use, differ to the metal one which may easily get rust and pollute your water. Package: comes with 10 pieces filter bags, zipper closure design, it is very ventilate for fish to stay inside for its mesh grids, convenient for you to fill and empty bags, not easy for fish to escape. Function: 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. Colour:black+white Material:polyester Size:15 x 20cm Package Contents: 5 * white filter bag 5 * black filter bag Only the above package content, other products are not included. Note: Light shooting 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.