Nano-filtration membranes offer many of the benefits of RO but remove less minerals (80% vs 99%), waste far less water (waste:product ratio of 1:1 instead of 4:1) and offer improved capacity. This filter set can be used to upgrade any standard 50GPD RO system to a nano-filtration system. Replacement filter set for 5-Stage RO or NF system. This set should be replaced every 24-months. Includes: - 5-micron Melt Blown Sediment Filter (2.5 x10" cartridge size) - Granular Activated Carbon Filter (2.5 x10" cartridge size) - 5-micron Carbon Block Filter (2.5 x10" cartridge size) - In-line Taste & Odour Filter (2x10" inline filter size) - 150GPD Nano-filtration membrane (1812 membrane size)