The Small Zip Bag is a mesh bag for holding filtration media. It is available in a 32 cm x 14 cm (12.5 x 5.5) size, easily holds 1 liter of filtration media, and it comes with a convenient corrosion-resistant zipper. It has a mesh size that is capable of holding small to intermediate and larger sized filter media including PhosGuard, MatrixCarbon, SeaGel, de-nitrate, Renew, Matrix, Zeolite. (Do not use with resins)