Baquler 30 Pcs Filter Media Compatible with Fluval 306 307 406 407 Water Polishing Pads Polishing Filter PadsBrand: Baquler Color: white Features: Generous Quantities: each package includes 30 pieces of water polishing pad; The ample quantity included gives you enough to replace your filters regularly for nice performance; A monthly change is recommended to ensure effective filtration Appropriate Size: with measurements of approximately 4. 33 x 2. 76 x 1. 42 inches 11 x 7 x 3. 6 cm, the water polishing pad for aquarium is compatible with Fluval 306 307 406