Crystal Clear Big Blue 5 Micron Whole House Sediment Water Filter 4.5" x 20" (2 Pack) Gradient Density, Multi-Layered, Melt Blown Sediment Filter Cartridge. Larger particles are trapped in the outer layers, smaller particles penetrate deeper. Greater dirt holding ability and longer life than non-layered cartridges. Reverse Osmosis Prefiltration Meets FDA requirements for food and beverage contact