Fortress Filtration Qty(20) Sediment 5 Micron 10" x 4.5" Water Filters RO/Cartridges/Big Blue/WVO Fortress Filtration Premium Water Filters Full Case of 20 Sediment Filters!! 5 Micron, 10" x 4.5" In Stock - Ready to Ship!! - These are standard sized filters and fit most 10" x 4.5" water filter housings. With Fortress Filtration products, you are being protected by the best!