Echo RO Filters The Echo Reverse Osmosis Filter will provide you with clean fresh tasting water. But in order to keep the system running at optimum levels you must replace the filters at regular intervals. We have 4 filter cartridges: Filter Cartridge Function Replacement Cycle Spun PP Filter (LABELED 1, or PP) Removes larger particles suspended in water. 3 - 6 months Carbon Block Filter (LABELED 2, or CTO) Removes organics, chlorine, odor, and turbidity. 3 - 6 months RO Membrane (LABELED 3, or RO) Removes bacteria, heavy metals, dissolved matter, and salinity. 12 - 24 months Post Activated Carbon Filter (LABELED 4, or TT3) Removes residual chlorine and odor. It also improves the taste of purified water. 3 - 6 months Specs & Features Replacement filters for your Echo RO Change out your filters at regular intervals for optimal performance Purify your water, getting rid of 99% of contaminants Buy all filters together or separately Easy to change out Product Specs: Weight: 7.5 lbs Product Dimensions: PP1 filter: 14 x 4 x 4 in CT02 filter: 14 x 4 x 4 in RO03 filter: 14 x 4 x 4 in T334 filter: 8 x 4 x 4 in Shipping Dimensions: 14 x 10 x 10 in