The Medium 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 intermediate and larger sized filter media including PhosGuard MatrixCarbon SeaGel de❊nitrate Renew Matrix Zeolite Sizes 32 cm x 14 cm (12 5” x 5 5”)